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August 2016

CONVENIENT ETHERIFICATION USING CONVENIENT ETHERIFICATION USING

TRICHLOROACETIMIDATES AND SYNTHESIS OF AMINOSTEROID TRICHLOROACETIMIDATES AND SYNTHESIS OF AMINOSTEROID

SHIP INHIBITORS SHIP INHIBITORS

Kyle Timothy Howard Syracuse University

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Abstract

Alcohols are a common form of functionality in organic chemistry, and are often present

in biologically active molecules. The protection of hydroxy groups is crucial in long multi-step

synthetic routes, as the unprotected alcohol is typically not compatible with many reagents.

Alcohols are often protected as corresponding benzyl ether, which can then be removed when

desired to reveal the alcohol functional group. Classic methodology for protection of alcohols as

benzyl ethers requires harsh conditions utilizing strong acids and bases, which functions well for

simple substrates. In more complex multifunctional molecules this can lead to degradation and

side products. Therefore, there is a need for the development of milder conditions for the

protection of alcohols.

Recently a number of reagents have been developed to form benzyl ethers under mild,

neutral conditions that and do not disturb the sensitive functionality in complex molecules.

Many of these reagents have been based on imidate-type systems. The most common imidate

system, the trichloroacetimidate, is often utilized for the installation of ethers under Lewis acid

catalyzed conditions. Given their ready availability, a reevaluation of the reactivity of alcohols

and trichloroacetimidates has been undertaken. In many cases, simply heating the imidate with

an alcohol in refluxing toluene without an exogenous acid or base is an effective method for the

formation of the desired ether. This operationally simple procedure is most effective for

trichloroacetimidates that are precursors to highly stabilized cations (i.e. the 4-methoxybenzyl

and diphenylmethyl group). The use of this new procedure with a number of acid and base

sensitive substrates, which are protected in excellent yield without disturbing the delicate

functionality present in these molecules, is presented.

Cancer is a group of disorders that are all defined by abnormal cell growth in an

organism. This is a very broad set of diseases that can affect multiple organs. While classic

cancer treatments have focused on killing all cells that divide quickly, more modern treatments

attempt to selectively stop cancer progression by influencing cell signaling pathways. There are

many studies about how cancer cells coopt cell signaling pathways and use these systems, which

control cell growth in normal cells, to facilitate their own uncontrolled progression. One of the

major cell signaling pathways implicated in tumor development is the PI3K pathway, which is

governed by the kinase PI3K and the phosphatases PTEN and SHIP.

SHIP1 is an SH2-containing inositol 5’-phosphatase found in blood cells that is

responsible for the hydrolysis of phosphatidylinositol-3,4,5-trisphosphate to

phosphatidylinositol-4,5-bisphosphate. This enzyme is part of a major cellular signaling

pathway (the PI3K pathway) that controls many important cellular events such as proliferation,

differentiation and adhesion. SHIP1 inhibition has been found to increase blood cell production

and slow the growth of blood cancer cells. Certain aminosteroids show selectivity as SHIP1

inhibitors and therefore may have therapeutic applications. In this study, syntheses of a number

of aminosteroid derivatives were performed and these compounds are evaluated for their

potential as SHIP1 inhibitors.

CONVENIENT ETHERIFICATION USING TRICHLOROACETIMIDATES AND

SYNTHESIS OF AMINOSTEROID SHIP INHIBITORS

By

Kyle T. Howard

Bachelor of Science in Chemistry, York College of Pennsylvania, York, PA, 2010

Master of Philosophy in Chemistry, Syracuse University, Syracuse, NY, 2012

DISSERTATION

Submitted in partial fulfillment of the requirements for the degree of

Doctor of Philosophy in Chemistry

Syracuse University

August 2016

Copyright © Kyle Howard 2016

All Rights Reserved

v

ACKNOWLEDGEMENTS

Pursuing my graduate degree at Syracuse University has been a challenging experience full of

learning, growth, and self-discovery. I consider myself very fortunate to have had this

experience. Along this journey I have met many people whom made me a better person.

Graduate school would have been extremely difficult without new friends and the support of

loved ones at home. To all these people, I owe immense gratitude.

First and foremost, I would like to thank my research advisor, Dr. John Chisholm. You are

truly a remarkable mentor. I admire your knowledge, patience, and ability to perform the many

jobs of an advisor. I am extremely grateful to have the opportunity to study under your

leadership. I know I would not have been successful at Syracuse University had it not been for

your guidance.

My laboratory mentors and coworkers, Dr. Dennis Viernes and Christopher Russo. I

appreciate all the laboratory training and guidance you gave me. Thank you for welcoming me

into the group and tolerating my endless questions.

My research coworkers, Arijit Adhikari, Daniel Wallach, Jigisha Shah, Brian Duffy,

Nivedita Mahajani, Otto Dungan, Bhaskar Joshi, and Alexandre Dixon. Thank you for

sharing in all the laboratory shenanigans, frustrations, successes, and celebrations.

Group members past and present, Matthew Linaburg, Patrick Stege, Brittni Kellum, Wilfried

Banko, Allen Prusinowski, Katie Armstrong, Lea Radal, and Tamie Suzuki. It has been a

pleasure getting to know you all.

Our research collaborator from SUNY Upstate Medical University, Dr. William Kerr and his

students Robert Brooks, Saundra Fernandes, Sonia Iyer, and Neetu Srivastava. Thank you

for the opportunity for this collaborative research.

Syracuse University professors, Dr. Nancy Totah, Dr. Yan-Yeung Luk, Dr. Daniel Clark, Dr.

Michael Sponsler, Dr. Kevin Sweder, Dr. James Hougland, Dr. James Kallmerten, Dr.

Weiwei Zheng. Thank you for your instruction and support during my time at SU.

My professors at York College of Pennsylvania. Dr. Kathleen Halligan, you have continued to

inspire me and support my career in chemistry. Thank you for investing so much time in me and

encouraging me to pursue a higher education. Dr. Gregory Foy, Dr. William Steel, Dr. James

Foresman, Dr. Keith Peterman, Professor William Glenwright, Professor Barbara Mowery

and Professor Tina Tao Maynes. I had such an amazing experience studying chemistry at YCP

and I owe it all to the great faculty of the chemistry department.

The staff of the Department of Chemistry, Cathy Voorhees, Jodi Randall, Joyce Lagoe, Linda

DeMauro, Deb Maley, Nancy Virgil, Anne Dovciak, Steve Rich, Sally Prasch, Michael

vi

Brandt, Deborah Kerwood, April LePage, and ElizaBeth Molloy. I appreciate all the help

you have extended to me.

To my amazing friends. Lauren Kaminsky, we started this journey together the first day of

orientation at YCP all the way to becoming doctors of chemistry at SU. Thank you doesn’t come

close to displaying my appreciation for you being an awesome person, roommate, and friend.

Susan Flynn, I am so thankful for meeting you my first year of grad school. Your humor and

kindness kept me going in the most stressful and difficult situations. Rabeka Alam and Jen

Elward, WE UNCLE BOBBY’S KIDS! Thank you for all the inside jokes, fun adventures, and

yummy dinner parties! Valerie Simons and Kathryn Roberts, thank you for being fantastic

roommates and allowing me to de-stress after a long day in the lab. Amanda Goulden, Keri

Diller, Cody Messinger, Matthew Artz, and Ashley Melber, thank you for visiting me in

Syracuse and being a constant support system when I visit home. You have truly been there for

me through the good times and the bad times. Erica Paige Monnin, you are one of the most

significant people in my life. I am so thankful for our friendship and you always having my

back. I hope we have many more days of coffee drinking, Taco Bell eating, and loving

friendship. Nick Goffard, Michael Riley, Kathy Calella, Brian Hopkins, Christopher

Griffith, Amit Taneja, Joey Simon, Tiffany Brec, Nicole Brec, Kerry Foxx, Justin McVey,

Alejandro Amezcua, Christina Rodgers, and Aerik Radley, thank you for accepting my

queerness and teaching me to be comfortable in my own skin. I value everything I have learned

from you and all the memories you created with me.

Lastly I have to thank my mother, father, and sister, Cheryl, Timothy, and Katelyn Howard.

Thank you for supporting my decision to attend graduate school. You all have been so

influential in my life and I cannot thank you enough for the constant support. The unconditional

love you displayed for me is amazing. I appreciate everything you have done for me from the

warm care packages in the cold Syracuse winter to the family trips to Niagara Falls and Mexico!

The sacrifices that you made were remarkable and I would not be here without you.

vii

TABLE OF CONTENTS

Abstract i

Title Page iii

Acknowledgements v

Table of Contents vii

List of Figures ix

List of Tables xi

Abbreviations and Acronyms xii

Dedication xvi

Chapter 1 FORMATION OF ETHERS UNDER MILD CONDITIONS

Abstract 1

Introduction 1

Formation of Ethers with Trichloroacetimidates 2

Protecting groups 2

Carbohydrates 3

Trifluoroacetimidates 3

Etherification using Triazinylammonium salts 4

Phosphinimidate Reagents 5

Etherification with Pyridinium Salts 5

References 7

Chapter 2 FORMATION OF PMB AND DPM ETHERS WITH

TRICHLOROACETIMIDATES UNDER THERMAL CONDITIONS

Abstract 9

Carboxylic acid esterification 9

Alkylation of thiols with trichloroacetimidates 14

Etherification of alcohols using trichloroacetimidates 16

Future Work 33

Experimental Procedures 34

Appendix A. 1H and 13C NMR Spectra Supplement to Chapter 2 63

References 140

Chapter 3 SYNTHETIC STUDIES TOWARD SHIP1 INHIBITORS

Abstract 146

PI3K Signaling Pathway 146

SHIP 149

Different isoforms 149

Structure of enzyme 150

X-ray structure of SHIP2 150

Rationale for SHIP Antagonist or Agonist 151

Cancer 151

Bone Marrow Transplantation 152

Stem Cell Mobilization and Transplantation 152

Blood Cell Production 153

viii

Obesity 153

Structure Activity Relationship/Design of Inhibitors 154

Tailless Steroid Derivatives 157

Results and Discussion 158

Conclusions 166

Experimental Procedures 167

Appendix B. 1H and 13C NMR Spectra Supplement to Chapter 3 184

References 195

CURRICULUM VITAE 199

ix

LIST OF FIGURES

Figure 1.1 Acid catalyzed DPM etherification with trichloroacetimidate 1.1 3

Figure 1.2 Glycosidic bond formation with trichloroacetimidate 3

Figure 1.3 Alkylation with trifluoroacetimidate 4

Figure 1.4 Ether Formation with Triazinylammonium salts 5

Figure 1.5 Alkylation with Phosphinimidates 5

Figure 1.6 Etherification with Pyridinium Salts 6

Figure 2.1 Proposed Mechanisms of PMB esterification 11

Figure 2.2 Esterification with DPM Imidate 14

Figure 2.3 Sulfide formation with imidates 15

Figure 2.4 Mechanistic Possibilities for thioether formation 16

with trichloroacetimidates

Figure 2.5 Thiol reaction with chiral imidate 16

Figure 2.6 Synthesis of DPM Imidate 18

Figure 2.7 Intercepting the DPM cation 19

Figure 2.8 The Overman rearrangement 19

Figure 2.9 Chiral DPM ethers 23

Figure 2.10 Neat PMB Ether Reactions 25

Figure 2.11 Concentration Studies 26

Figure 2.12 PMB Etherification with Cinnamyl Alcohol 27

Figure 2.13 PMB Etherification with Cinnamyl Alcohol in α,α,α-Trifluorotoluene 28

Figure 2.14 Hydrogen bonding in diols 32

Figure 2.15 One Pot PMB Etherification 33

Figure 3.1 The PI3K Pathway 148

Figure 3.2 The PI3K Signaling Cascade 149

x

Figure 3.3 Crystal Structure of SHIP2 150

Figure 3.4 SHIP Inhibitors 154

Figure 3.5 Aminosteroid Analogues 155

Figure 3.6 Structure Activity Relationship of the Aminosteroid SHIP inhibitors 155

Figure 3.7 Proposed model of active site for SHIP1 156

Figure 3.8 SHIP Inhibition with Aminosteroids 157

Figure 3.9 SHIP1 Inhibitors and Potential Analogues 158

Figure 3.10 Clemmensen Reduction of Trans-Androsterone 158

Figure 3.11 Synthesis of K185 161

Figure 3.12 Synthesis of K118 162

Figure 3.13 Synthesis of Aminosteroid K179 163

Figure 3.14 Synthesis of Alkene 3.16 164

Figure 3.15 Synthesis of Potential SHIP Inhibitor 3.17 165

Figure 3.16 %SHIP Inhibition with Aminosteroids 166

xi

LIST OF TABLES

Table 2.1 Esterification with PMB Imidate 12

Table 2.2 Solvent Screen of Etherification with DPM Imidate 20

Table 2.3 Etherification with DPM Imidate 21

Table 2.4 PMB Ether Solvent Screen 25

Table 2.5 PMB Etherifications in α,α,α-Trifluorotoluene 29

Table 2.6 PMB Etherification of Diols 32

Table 3.1 Clemmensen Reduction of Trans-Androsterone 159

Table 3.2 Hydrazone Reduction Conditions 160

xii

ABBREVIATIONS AND ACRONYMS

[α] Specific rotation

3AC 3α–aminocholestane

Akt Protein kinase B

Akt1 Protein kinase B 1

Akt2 Protein kinase B 2

AIBN Azobisisobutyronitrile

AML Acute myelogenous leukemia

Anal. Combustion elemental analysis

anhyd Anhydrous

ATG Authophagy–related

BAECs Bovine aortic endothelial cells

bFGF Basic fibroblast growth factor

BHT Butylated hydroxytoluene

BM Bone marrow

BMMC Bone marrow mast cell

bs Broad singlet

Btk Bruton’s tyrosine kinase

calcd Calculated

CD Crohn’s Disease

CF Cystic fibrosis

CI Chemical ionization

CLogP Calculated partition coefficient

cod 1,5–Cyclooctadiene

compd Compound

concd Concentrated

COSMIC College of Science Major Instrumentation

CSA Camphorsulfonic acid

Cy Cyclohexyl

Chemical shift in part per million

DCB 1,4–Dichlorobenzene

DCE 1,2–Dichloroethane

DCM Dichloromethane

DBU 1,8–Diazabicyclo[5.4.0]undec–7–ene

DEPT Distortionless enhancement by polarization transfer

DIAD Diisopropyl azodicarboxylate

DIBAL Diisobutylaluminum hydride

DMAP 4–Dimethyl aminopyridine

dba Dibenzylideneacetone

DMF Dimethylformamide

DMP Dess–Martin periodinane

DMPU 1,3–dimethyl–3,4,5,6–tetrahydro–2(1H)–pyrimidinone

DMSO Dimethyl sulfoxide

DPM Diphenyl methyl

EGF Epidermal growth factor

xiii

EGFR Epidermal growth factor receptor

ERK Extracellular regulated kinase

ES Embryonic stem

ESI Electrospray ionization

FP Fluorescence polarization

FT Fourier transform

Gab Grb2–associated binding

Glut4 Glucose transporter type 4

Grp1 General receptor for phosphoinositides 1

GSK3β Glycogen synthase kinase 3

GTP Guanosine triphosphate

GvHD Graft vs. Host disease

H&E Hematoxylin and Eosin

HGF Hepatocyte growth factor

HIV Human immunodeficiency virus

HMBC Heteronuclear multiple bond correlation

HRMS High–resolution mass spectroscopy

HSC Hematopoietic stem cells

HTS High–throughput screening

HWE Horner–Wadsworth–Emmons

IBD Inflammatory bowel disease

IC50 Half maximal inhibitory concentration

I–1,3,4,5–P4 Inositol–1,3,4,5–tetrakisphosphate

IL–1β Interleukin–1β

IP Inositol phospholipid

IP4 Inositol–1,2,4,5–tetrakisphosphate

JNK c–Jun N–terminal kinases

KD Equilibrium dissociation constant

LAH Lithium aluminum hydride

LDA Lithium diisopropylamine

lit. Literature value

LN Lymph node

MAP Mitogen–activated protein

MAPK Mitogen–activated protein kinases

m–CPBA meta–Chloroperoxybenzoic acid

MEF Mouse embryonic fibroblasts

Mes 2,4,6–Trimethylphenyl (mesityl)

MDCK Madin–Darby canine kidney

MG+ Malachite Green

MIR Myeloid immunoregulatory

MM Multiple myeloma

MOM Methoxymethyl

Ms Methylsulfonyl (mesyl)

MS Molecular sieves

MySCs Myeloid suppressor cells

NCI National Cancer Institute

xiv

NHK Nozaki–Hiyama–Kishi

NK Natural killer

NMO N–Methylmorpholine N–oxide

NMR Nuclear Magnetic Resonance

NO Nitrite

NOESY Nuclear Overhauser effect spectroscopy

PCC Pyridinium chlorochromate

PDC Pyridinium dichlorochromane

PDK1 Phosphatidylinositide kinase 1

PH Pleckstrin homology

PI3K Phosphatidylinositol–3–kinase

PI–3,4–P2 Phosphatidylinositol–3,4–bisphosphate

PI–3,4,5–P3 Phosphatidylinositol–3,4,5–trisphosphate

PIPn Phospoinositides

Piv Pivalate

PKB Protein kinase B

PLC–γ Phospholipase C–γ

PMB para-methoxybenzyl

PMP para–Methoxyphenyl

PPTS Pyridinium para–toluenesulfonate

PTEN Phosphatase and tensin homolog

PTH Parathyroid hormone

p–TsCl para–Toluenesulfonyl chloride

Ras Receptor tyrosine kinases

RBC Red blood cell

rt Room temperature

SAR Structure–activity relationship

Shc Src homology 2–containing

SH2 Src homology 2 containing

SHIP Src homology 2 domain–containing inositol 5’–phosphatase

SHIP1 Src homology 2 domain–containing inositol 5’–phosphatase 1

SNPs Single–nucleotide polymorphisms

TBAF Tetrabutylammonium fluoride

TBS tert–Butyldimethylsilyl

TBDPS tert–Butyldiphenylsilyl

TEMPO 2,2,6,6–Tetramethylpiperidin–1–oxyl

TES Triethylsilyl

TFA Trifluoroacetic acid

TFAA Trifluoroacetic anhydride

TFP Tri–2–furylphosphine

THP Tetrahydropyran–2–yl

TMEDA N,N,N,N–Tetramethylethylenediamine

TMS Tetramethylsilane

THF Tetrahydrofuran

TIPS Triisopropyl

TLC Thin layer chromatography

xv

TMS Tetramethylsilane

Tf Trifluoromethanesulfonyl (triflyl)

Ts para–Toluenesulfonyl (tosyl)

V–ATPases Vacuolar (H+)–ATPases

Yphos Tyrosine phosphorylated

xvi

DEDICATION

For my family, Dad, Mom, Katelyn,

Grandpa Ed, Grandma Doris, Grandpa Frank and Grandma Ida.

“True wealth is having a healthy mind, body, and spirit. True wealth is having the knowledge to

maneuver and navigate the mental obstacles that inhibit your ability to soar. Remember to love

yourself, because if you can’t love yourself, how in the hell are you gonna love somebody else?”

-RuPaul

1

Chapter 1: Formation of Ethers Under Mild Conditions

Abstract:

Alcohols are common in organic molecules, and are often present in biologically active

natural products. The protection of hydroxy groups is critical in long multi-step synthetic routes,

as the unprotected alcohol is typically not compatible with many reagents. Alcohols are often

protected as benzyl ethers or substituted benzyl ethers, which can then be removed under a

variety of conditions when desired. Classic protection methods for alcohols as benzyl ethers

requires harsh conditions utilizing strong acids and bases, which functions well for simple

substrates. In more complex polyfunctional molecules this can lead to degradation and side

products. Therefore, there is a need for the development of milder conditions for the protection

of alcohols. Recently a number of reagents have been developed to form benzyl ethers under

mild, neutral conditions that and do not disturb sensitive functionality. This chapter provides

details of many of these reagents and summarizes the conditions needed to install the ethers

utilizing these new methods.

Introduction:

Ethers are of great value in organic synthesis since they can act as protecting groups for

sensitive alcohols.1,2 Simple and mild conditions are often desired to protect and deprotect

alcohol substrates as to minimize degradation of a multistep synthesis. There are many known

procedures to make ethers with the Williamson ether synthesis being a popular method. Another

classical method for ether synthesis is the Koenigs-Knorr reaction for glycoside formation. Both

methods employ the use of basic alkali metal alkoxides with alkyl halides. Alternatively ethers

may be formed from alcohols under acidic conditions. These methods can be problematic in the

2

protection of alcohols in complex molecules. For example, carbohydrates can undergo base

catalyzed migration of esters and silyl ethers. Silyl ethers and acetal linkages could also be

disturbed by acid catalyzed cleavage. Metal catalysts have also been employed for the formation

of ethers, however, they are usually expensive.3,4 Therefore, development of milder conditions

for the protection of complex alcohols so that other sensitive functionality is not disturbed in

complex molecules is an ongoing area of research.

Recently several different reagents have been advanced for the protection of alcohols in

complex molecules without disturbing delicate functionality. One often cited method is to use

the trichloroacetimidate to form the ether in the presence of a Brønsted or Lewis acid. This

methodology is especially useful for the introduction of benzyl, allyl, and 4-methoxybenzyl

ethers.5,6,7 Other benzylic ethers have also been formed under these conditions. For example, the

formation of DPM ethers have been reported with the use of trichloroacetimidates and Lewis

acids (Figure 1.1).8,9 Diphenylmethyl trichloroacetimidate can be easily prepared with

diphenylmethanol and trichloroacetonitrile and is stable at room temperature over long periods of

time. The facile formation of DPM ethers with DPM imidate in the presence of TMSOTf

worked well on various primary and secondary alcohols. This methodology was showcased in

the creation of glycosidic bonds. Because the diphenylmethyl group on an -alcohol at the 2-O

position sterically hinders α bond formation, it facilitates stereoselective β-glucopyranoside

formation.

3

Figure 1.1: Acid catalyzed DPM etherification with trichloroacetimidate 1.1

Schmidt and Michel have demonstrated a use for trichloroacetimidates in glycosidic bond

formation.10 Facile conversion of the glucopyranose to the corresponding imidate is done with

base and trichloroacetonitrile or aryl-substituted ketenimines. Then the isolated imidate can be

used for an acid catalyzed reaction with another glucopyranose to form a glycosidic bond (Figure

1.2). This methodology avoids using heavy metal salts such silver salts which were previously

utilized for glycoside synthesis.

Figure 1.2: Glycosidic bond formation with trichloroacetimidate

Trifluoroacetimidates have also been utilized in the benzylation of alcohols.11,12 These

imidates can be prepared from a one pot reaction of benzyl alcohols via perfluoro nitriles from an

amide dehydration. Perfluoro nitriles can be difficult to use since they are extremely volatile and

toxic. In a related study, Pohl investigated a number of N-aryl trifluoroacetimidates for the

installation of benzyl and allyl protecting groups on carbohydrates (Figure 1.3). These

trifluoroacetimidates are prepared from N-aryl trifluoroacetimidoyl chlorides, benzyl or allyl

alcohol and base. Employing an electron withdrawing phenyl group on the nitrogen of the

4

imidate allows for a more stable imidate but still provides reactivity as a leaving group. The

perfluoroacetimidates are stable at room temperature for several days. These imidates have been

reported to alkylate alcohols in one hour at room temperature. However, the alkylation employs

the use of an acid catalyst such as TfOH or TMSOTf.

Figure 1.3: Alkylation with Trifluoroacetimidate

Kunishima also established a method for preparing benzyl ethers at room temperature

with triazinylammonium salts (Figure 1.4). 4-(4,6-Diphenoxy-1,3,5-triazin-2-yl)-4-

benzylmorpholinium trifluoromethanesulfonate (DPT-BM) is prepared from 4,6-diphenoxy-2-

trifluoromethanesulfonyloxy-1,3,5-triazine and 4-benzylmorpholine.13 This triazinylammonium

salt is a non-hygroscopic, stable solid and can be stored at cold temperatures for long periods of

time. This reagent was used to benzylate primary, secondary and tertiary alcohols in high yields.

This alkylation also performed well on acid and base sensitive substrates such as acetoxy, β-

hydroxyester, and silyl groups. The major caveat with this reaction is that it uses MgO as an acid

scavenger and dehydrating reagent, which introduces another variable into the reaction and could

lead to degradation of sensitive molecules. Kunishima has also reported alkylation of alcohols

with benzyl or p-methoxybenzyl groups using 2,4,6-tris(benzyloxy)-1,3,5-triazine (TriBOT) and

2,4,6-tris(p-methoxybenzyloxy)-1,3,5-triazine (TriBOT-PM), respectively.14, 15 However, this

method also uses catalytic acid to make the corresponding ethers.

5

Figure 1.4: Ether Formation with Triazinylammonium salts:

Phosphinimidates have also been explored for their use in the alkylation of alcohols

(Figure 1.5) under mild conditions.16 These stable imidates are made from alkyl

diphenylphosphinites and methanesulfonyl azide. The ether formation worked well when a

strong electron withdrawing group was bonded to the nitrogen of the phosphinimidate. The

alkylation was also quite general, and performed well on primary, secondary and tertiary

alcohols as well as carbohydrates. One drawback to using phosphinimidates as alkylating agents

is that they need catalytic amount of TMSOTf for the transformations to occur.

Figure 1.5: Alkylation with Phosphinimidates

Dudley has reported the protection of alcohols as benzyl and p-methoxybenzyl groups

using 2-benzyloxy-1-methylpyridinium triflate (Bn-OPT) and 2-(4-methoxybenzyloxy)-4-

methylquinoline, respectively, in refluxing α,α,α-trifluorotoluene (Figure 1.6).17 Bn-OPT is a

6

novel benzylation reagent for alcohols, stable solid, and preactivated. It is prepared by treating

2-benzyloxypyridine with methyl triflate and can be made in situ in the presence of alcohol. The

benzylation works well with primary, secondary, and tertiary alcohols. This etherification also

worked with β-hydroxyesters and trimethylsilylethanol. However, reaction with cinnamyl

alcohol only provided trace amounts of product. Additionally in order to prepare this reagent,

the toxic and carcinogenic methyl triflate must be prepared and used. Alkylation with 2-(4-

methoxybenzyloxy)-4-methylquinoline also worked on primary, secondary, and tertiary alcohols.

This method created by Dudley use additives such as MgO which is a mild base and desiccant to

scavenge acid or water. Therefore, this etherification could prove difficult with base sensitive

functionality.

Figure 1.6: Etherification with Pyridinium Salts

While many reagents have been created to address the problem of protecting alcohols

under mild conditions in sensitive systems, work towards a general, inexpensive and nontoxic

solution which does not require a strong acid catalyst is still ongoing. In the next chapter we will

discuss investigations into utilizing trichloroacetimidates for these transformations without the

addition of an acid promoter, providing an alternative solution for the formation of some esters

and ethers under mild conditions.

7

References

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Wiley & Sons: Hoboken, NJ, 2006; pp 610–611.

2. Kocienski, P. J. Protecting Groups, 3rd Ed.; Thieme: Stuttgart, 2005; pp 409–417.

3. Bikard, Y.; Weibel, J.-M.; Sirlin, C.; Dupuis, L.; Loeffler, J.-P.; Pale, P. Tetrahedron

Lett. 2007, 48, 8895-8899.

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14. Yamada, K.; Fujita, H.; Kunishima, M. Org. Lett. 2012, 14, 5026-5029.

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16. Aoki, H.; Mukaiyama, T. Chem. Lett. 2005, 34, 1016-1017.

17. (a) Poon, K. W. C.; House, S. E.; Dudley, G. B. Synlett. 2005, 3142-3144; (b) Poon,

K. W. C.; Albiniak, P. A.; Dudley, G. B. Org. Synth. 2007, 84, 295-305; (c) Albiniak,

P. A.; Dudley, G. B. Synlett. 2010, 841-851; (d) Tummatorn, J.; Albiniak, P. A.;

Dudley, G. B. J. Org. Chem. 2007, 72, 8962-8964; (e) Wang, T.-W.; Intaranukulkit,

T.; Rosana, M. R.; Slegeris, R.; Simon, J.; Dudley, G. B. Org. Biomol. Chem. 2012,

10, 248-250. (f) Nwoye, E. O.; Dudley, G. B. Chem. Commun. 2007, 1436-1437. (g)

Poon, K. W. C.; Dudley, G. B. J. Org. Chem. 2006, 71, 3923-3927.

9

Chapter 2: Formation of Esters, Thioethers and Ethers with Trichloroacetimidate

Electrophiles under Catalyst-Free Conditions

Abstract:

Many reagents have been developed to form benzyl ethers and esters under mild, neutral

conditions that and do not disturb the sensitive functionality in complex molecules. Most of

these reagents are based on acetimidate-type systems, as the rearrangement of these systems to

the corresponding acetamide provides a secondary thermodynamic driving force for the ether

formation. Trichloroacetimidates are effective at alkylating carboxylic acids, thiols, and alcohols

under Lewis acid catalyzed conditions, but little attention has been given to their reactivity under

catalyst free conditions. Given their ready availability, a reevaluation of the reactivity of

alcohols and trichloroacetimidates has been undertaken. In many cases, simply heating the

trichloroacetimidate with an alcohol in refluxing toluene without an exogenous acid or base is an

effective method for the formation of the desired ether. This operationally simple procedure is

most effective for trichloroacetimidates that are precursors to highly stabilized cations (i.e. the 4-

methoxybenzyl and diphenylmethyl group). Esters, thioethers and ethers were formed without

the use of an acid or base catalyst. Thermal etherification was performed under neutral

conditions with both the DPM and PMB trichloroacetimidate. The use of this new procedure

with a number of acid and base sensitive substrates, which are protected in excellent yield

without disturbing the delicate functionality present in these molecules, is presented.

1. Catalyst-Free Protection of Esters with Trichloroacetimidates

Carboxylic acids are often protected as esters in multistep organic synthesis. Popular ester

protecting groups for carboxylic acids include the 4-methoxybenzyl (PMB) and diphenylmethyl

(DPM) esters.1,2 These protecting groups are often used due to their ease of removal via treatment

10

with acid or by hydrogenation (they may also be removed by saponification).1-7 Carboxylic acids

are typically protected with a PMB group through alkylation reactions with the corresponding

halide and a strong base. DPM esters can be installed with acid catalysis using diphenylmethanol

as the electrophile or by treating the carboxylic acid with diphenyldiazomethane.8,9,10 The problem

with most of these protecting group installations is that they do not tolerate complex substrates

with sensitive functionality or they incorporate environmentally hazardous reagents.9

Trichloroacetimidates have been used for ester formation through their reaction with carboxylic

acids in the presence of an acid catalyst.11 There have been scattered reports of ester formation

with trichloroacetimidates without the addition of a catalyst, however. For example, Hayashi and

co-workers have reported the formation of a PMB ester without a catalyst using 4-methoxybenzyl-

2,2,2-trichloroacetimidate directly.3,4 Two other examples of catalyst free esterification are also

present in the literature, with glycosyl imidates and 2-phenylisopropyl trichloroacetimidate

undergoing these reactions.12,13 In the examples where a catalyst is not needed for esterification,

the imidate may be protonated by the carboxylic acid and then ionize to form a carbocation, which

is then trapped by the carboxylate anion. All of these examples of ester formation with

trichloroacetimidates use imidates that are precursors to stable carbocations. Loss of the imidate

and formation of trichloroacetamide thermodynamically facilitates the alkylation reaction. Given

that little was known about the scope of these reactions, an investigation using PMB and DPM

trichloroacetimidates to form their respective esters of carboxylic acids without an acid catalyst

was initiated.

The formation of esters from trichloroacetimidates may occur by either an SN1 or an SN2

mechanism (Figure 2.1 shows the possible mechanisms for the reaction of a carboxylic acid with

PMB trichloroacetimidate 2.1). For SN1 addition, the carboxylic acid substrate promotes the

11

reaction by protonating the basic imidate nitrogen. After acetamide 2.3 is formed, the carboxylate

anion can add to the PMB cation. In SN2 addition, the carboxylic acid adds to the benzylic position

of the PMB imidate causing the acetamide anion to form. The acetamide anion then removes the

hydrogen from the protonated acid, forming the PMB ester. A concerted SN2 mechanism involving

a 6-membered transition state between the carboxylic acid and the PMB imidate is also a

possibility.

Figure 2.1: Proposed Mechanisms of PMB esterification

12

Ester formation without the presence of an acid catalyst using PMB imidate 2.1 was

initially explored. PMB imidate 2.1 is commercially available and may also be easily prepared

from PMB alcohol and trichloroacetonitrile using DBU or NaH as a catalyst.14 Several carboxylic

acids were successfully treated with PMB imidate 2.1 to form their corresponding esters without

an added acid catalyst (Table 2.1).15 This simple reaction is carried out at room temperature in

dichloromethane. Diverse substrates tolerated the esterification such as alkanes, alkenes, alkynes,

and electron rich and electron poor benzoic acids. Under these conditions, carboxylic acids are

selectively protected over other functional groups such as alcohols.

Table 2.1: Esterification with PMB Imidate

Entry Compound % Yield

1

43%

2

60%

3

54%

4

64%

13

5

50%

6

63%

7

80%

8

51%

9

27%

10

25%

Ester formation was successful for the compounds in Table 2.1, resulting in moderate to

high yields. Esterification of acetylsalicylic acid gave the highest yield of 80%. The isobutyl

ester in entry 1 provided a low yield most likely due to steric effects from the isobutyl group on

the acid. Entries 2 and 7 demonstrate that ortho substituents are tolerated on benzoic acid

derivatives for this methodology, so some tolerance of sterically demanding substrates was

demonstrated. No isomerization was observed for the alkene in entry 3. Entries 4, 5 and 6

provided moderate yields most likely due to sterics from the bulky R groups next to the

14

carboxylic acids. The highly strained cyclopropyl carboxylic acid provided the respective PMB

ester in 51 % yield (entry 8), but no opening of the cyclopropane was observed. Entries 9 and 10

again gave lower yields due to sterics of the corresponding carboxylic acids. This study provides

evidence that PMB esters can be formed under mild reaction conditions using the

trichloroacetimidate, and provides a mild method which may be useful for forming PMB esters

in complex multifunctional substrates.15 Sterically hindered carboxylic acids may provide lower

yields due to sterics, however.

Building on the success with PMB trichloroacetimidate, diphenyl methyl

trichloroacetimidate was evaluated as an esterification reagent under catalyst-free conditions

(Figure 2.2). Diphenylmethyl trichloroacetimidate was postulated to be an effective alkylating

agent because it can lead to a stabilized carbocation, facilitating the SN1 substitution pathway

with a carboxylic acid. Also, it is a easy to handle white solid that is stable in cold storage for

long periods of time and can be easily prepared from the inexpensive diphenylmethanol in high

yield.16 Ester formation was successful for both tert-butylacetic acid 2.15 and adamantane-1-

carboxylic acid 2.18 with DPM imidate 2.16 under neutral conditions. Esterification of tert-

butylacetic acid gave a high yield of 92% while adamantane-1-carboxylic acid was not as

reactive which is most likely because of sterics. This study provides evidence that DPM esters

such as 2.17 and 2.19 may also be formed under mild reaction conditions using the

trichloroacetimidates.17

15

Figure 2.2: Esterification with DPM Imidate

2. Thioethers

Building on the esterification work, the alkylation of thiols was then attempted under

catalyst-free conditions. Thiols are less acidic than alcohols, but more acidic than alcohols, so

their alkylation was explored next. Sulfides are commonly present in molecules used for

pharmaceuticals, enzyme cofactors, and pesticides.18,19,20 Sulfides are often synthesized from the

alkylation of thiols with alkyl halides or alcohols.21 However, these classic methods employ the

use of an acid or base catalyst, which may provide problems in complex molecules.22

Trichloroacetimidates were effective in the alkylation of thiols to form thioethers without

the addition of an acid, base or metal catalyst (Figure 2.3). This new method for sulfide

formation involves simply refluxing the thiol and imidate in THF. Both alkyl and aromatic thiols

can be used with this method. Also, a variety of trichloroacetimidates including alkyl, allylic,

propargylic and benzylic imidates performed well in the alkylation reaction.23

16

Figure 2.3: Sulfide formation with imidates

Figure 2.4 shows two mechanistic possibilities for this thiol alkylation. Depending on the

electrophile, this reaction can proceed through either a SN1 or SN2 pathway. The first step for

both mechanisms is the imidate gets protonated by the thiol, creating a thiolate anion. Should the

electrophile be suitable for SN2 conditions, the sulfur anion will attack with the R’ group from the

protonated imidate and the acetamide 2.3 is formed directly. A concerted SN2 process as shown

in Figure 2.1 may also be possible with a thiol. For the SN1 pathway, the protonated imidate

forms the acetamide and an R’ cation. Then the thiolate will then attack the R’ cation to give the

thioether.

17

Figure 2.4 Mechanistic possibilities for thioether formation with trichloroacetimidates

Thiol displacement of methyl trichloroacetimidate under these conditions to form a

methyl thioether supported the SN2 mechanism. Furthermore, thiol reaction with chiral imidate

supports an SN2 mechanism (Figure 2.5). The reaction proceeded with inversion forming sulfide

2.28, with none of the retention product being observed by 1H NMR (the retention product was

independently synthesized for comparison).

Figure 2.5: Thiol reaction with chiral imidate

3. Ethers

After formation of sulfides with trichloroacetimidates under catalyst free conditions,

attention was turned to the etherification of alcohols. Trichloroacetimidates have been routinely

used to protect alcohols as ethers at room temperature in the presence of a Brønsted or Lewis

acid catalyst.24-29 Schmidt and co-workers have employed diphenylmethyl trichloroacetimidate

2.16 to make diphenylmethyl (DPM) ethers with a catalytic amount of TMSOTf in excellent

18

yields.16 The use of an acid catalyst for this reaction limits the substrates which can participate

in the etherification. An example of a problematic acid sensitive substrate would be β-

trimethylsilylethanol, which has been reported to be subjected to a Peterson elimination under

acidic conditions with a trichloroacetimidate.30 Other reagents similar to trichloroacetimidates

have also been developed for the synthesis of benzyl and PMB ethers.31,32 Additionally,

trifluoroacetimidate and phosphinimidate type reagents have been introduced for etherification,

however these systems still require the use of an acid cataylst.33,34

Diphenylmethyl (DPM) ethers are frequently used as protecting groups for alcohols in

organic synthesis.35 They can easily be removed through hydrogenation or with acidic

conditions making the DPM group useful in complex molecules where more than one protecting

group is in place.36,24 DPM ethers have also proven beneficial for enantioselective reactions

since the steric bulk of the group can show increased selectivity in some substrates.37 The DPM

group is also commonly used in medicinal chemistry since the phenyl rings add large

hydrophobic groups which increase the lipophilicity of biologically active molecules.38

Trichloroacetimidates have been utilized in the Chisholm laboratory to explore ester and

sulfide formation.15,17,23 Given the high reactivity of the PMB and DPM trichloroacetimidates

with carboxylic acids and thiols, these substrates were chosen for initial exploration as

etherification reagents under catalyst-free conditions. PMB and DPM ethers are also commonly

used protecting groups, so these methods should have some utility in the synthetic organic

community. Studies with DPM imidate 2.16 have shown that the rearrangement of the imidate

to the corresponding acetamide occurs when the imidate is refluxed in toluene. This type of

rearrangement is similar to reports of benzylic imidates undergoing rearrangement through a

cationic pathway in the presence of a strong acid.39 We hypothesized that under thermal

19

conditions a similar process occurs and the DPM imidate ionizes to form a DPM cation and

trichloroacetamide anion. The cation could be intercepted by an external nucleophile such as an

alcohol. This hypothesis would allow for the formation of DPM ethers under thermal conditions

without the use of an acid or base additive. Conditions have now been developed for ether

formation under neutral conditions without a catalyst, which typically proceed in moderate to

high yields with DPM and PMB imidates.40

Diphenylmethyl (DPM) imidate was synthesized from benzophenone (Figure 2.6).

Reduction of benzophenone to diphenylmethanol is easily done with sodium borohydride in

methanol. The treatment of the diphenylmethanol with trichloroacetonitrile (TCAN) in the

presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) provided DPM imidate 2.16. Alfa-Aesar

quotes diphenylmethanol at $25.97/mol, TCAN at $36.94/mol and $38.06/mol, allowing for a

very cost effective synthesis of DPM imidate. The DPM imidate 2.16 showed stability for long

periods of time when stored cold in a refrigerator and is very easy to handle since its physical

form is a white powder.

Figure 2.6: Synthesis of DPM Imidate

Earlier studies with DPM imidate 2.16 demonstrated that the imidate would rearrange to

the corresponding trichloroacetamide when refluxed in toluene (Figure 2.7). Rearrangements of

allylic trichloroacetimidates are known and usually occur through a concerted [3,3]-sigmatropic

rearrangement (the Overman rearrangement, Figure 2.8).41 However, this rearrangement is less

favorable for the DPM imidate. Instead, the rearrangement is believed to occur through a

20

cationic pathway, where the imidate ionizes under thermal conditions due to the stability of the

diphenylmethyl cation. This allows cation 2.32 and trichloroacetamide anion 2.31 to form. The

trichloroacetamide anion is a weak base and poor nucleophile with a pKa of approximately 11.41

An added external nucleophile, such as an alcohol, may therefore intercept the cation 2.32 and

form the corresponding DPM ether.

Figure 2.7: Intercepting the DPM cation

Figure 2.8: The Overman rearrangement

Our thermal etherification studies began with an exploration of reaction conditions. A

solvent screen with 1-octadecanol 2.34 and DPM imidate 2.16 showed that performing the

reaction in toluene at reflux gave the best isolated yield of the corresponding DPM ether product

(Table 2.2, entry 1). Lower temperatures in toluene provided a lower yield of the desired ether

21

product (entry 2), which was attributed to a slower reaction. Nonpolar solvents appeared to be

superior for the etherification reaction, with acetonitrile and DMF providing the lowest yields

(entries 8 and 9 respectively).

Table 2.2: Solvent Screen of Etherification with DPM Imidate

Entry Solvent Temperature (oC) % Yield

1 Toluene 111 85

2 Toluene 50 24

3 Trifluorotoluene 102 62

4 1,2-Dichloroethane 83 66

5 Dichloromethane 40 18

6 Tetrahydrofuran 66 36

7 1,4-Dioxane 101 60

8 Acetonitrile 82 28

9 Dimethylformamide 110 33

This catalyst-free etherification was then evaluated with a variety of alcohols to

determine the scope of the reaction (Table 2.3). The reaction provided very high yields with

benzyl alcohols in entries 1, 2, 3, and 4. Entries 5, 6, 7, 8 show allylic alcohols and phenol

derivatives also participate in this reaction. Propargyl alcohol (entry 12) also proved to be an

excellent reactant in the transformation, providing a 97% yield of propargyl ether product. The

etherification of secondary and tertiary alcohols (entries 9, 10, 11) also proceeded in high yields.

This is notable, as many other catalyst-free etherification conditions do not provide high yields

with tertiary alcohols.30 Entries 13, 14, and 15 demonstrate that more complex alcohols can be

protected with this methodology. Acid and base sensitive alcohols may also be protected with

22

this procedure as shown in entries 16-18. The protection of 2-trimethylsilyl ethanol to form ether

2.53 is particularly notable, as this substrate decomposes under acidic and basic conditions,30 yet

is effectively protected under the new thermal conditions. Diols may also be mono protected

with this methodology (entries 21-24), although the yields are moderate. In the case of mono

protection only one equivalent of DPM imidate was used for the ether formation. Small amounts

of diprotected ether were observed for the symmetrical diols. Entries 23 and 24 gave low yields

because of the difficult separation of the mixture of mono protected alcohols. These reactions

demonstrate that DPM ethers can be formed with neutral conditions using trichloroacetimidates.

The ability to monoprotect alcohols preferentially may be explained by the greater acidity of the

diol when the two alcohols form an intramolecular hydrogen bond, this was further explored

with PMB trichloroacetimidate and is discussed later in this chapter.

Table 2.3: Etherification with DPM Imidate

Entry Alcohol % Yield

1

94%

2

71%

3

92%

4

88%

23

5

91%

6

61%

7

53%

8

88%

9

93 %

10

85%

11

92%

12

97%

13

80%

14

80%

15

96%

16

65%

17

73%

18

79%

24

19

90%

20

91%

21

68%

22

40%

23

38%

24

19%

No racemization was observed in the formation of chiral ethers 2.54 and 2.55 through

chiral HPLC analysis (Figure 2.8). Chiral and racemic serine protected ethers were prepared for

comparison on chiral HPLC. The chiral HPLC traces show that no racemization occurs under

the thermal etherification conditions. The same was observed for chiral ethyl lactate 2.54

(Figure 2.9).

25

Figure 2.9: Chiral DPM ethers

Since ether formation from alcohols performed well with DPM imidate, a study was

initiated with 4-methoxybenzyl (PMB) imidate. Both the PMB and DPM imidates have been

shown to react with carboxylic acids to form esters without the need for an acid catalyst, so the

PMB ether may also be reactive enough to form ethers under thermal conditions. PMB ethers are

more common protecting groups for alcohols and can be easily removed under mild oxidation

conditions.1,2 Since the PMB imidate is an oil, PMB protection under solvent free conditions

26

was initially explored (Figure 2.10). These neat reactions were performed with either 1-

octadecanol or cinnamyl alcohol and 3 equivalents of PMB imidate at 110 oC overnight. This

resulted in a good yield for 1-octadecanol, but only a 17% yield of the cinnamyl ether was

obtained under these conditions. The addition of 10 mol% trichloroacetamide was also explored

to see if the acetamide was catalyzing the reaction. The yield improved slightly for cinnamyl

alcohol with the addition of trichloroacetamide but had little effect in the case with 1-

octadecanol. As these conditions were not general and yields were moderate, a solvent screen

was performed for the PMB etherifications (Table 2.4).

Figure 2.10: Neat PMB Ether Reactions

27

Table 2.4: PMB Ether Solvent Screen

Entry Solvent Temperature (oC) % Yield

1 Toluene 111 70

2 Toluene 80 27

3 Toluene 50 23

4 Trifluorotoluene 102 73

5 1,2-Dichloroethane 83 74

6 Dichloromethane 40 17

7 Dichloromethane r.t. 4

8 Tetrahydrofuran 66 40

9 1,4-Dioxane 101 25

10 Acetonitrile 82 18

11 Dimethylformamide 110 11

*0.25 M concentration

The solvent screen showed dichloroethane at reflux giving the best yield of PMB ether

2.60. -Trifluorotoluene and toluene gave good yields when used at reflux. More polar

solvents did not give good yields, as the imidate decomposed rapidly under these conditions.

Less polar solvents at lower temperatures typically returned starting material, leading to the

conclusion that a temperature in excess of 80 °C was required for the etherification. Alcohol

protection with PMB imidate was therefore initially explored in DCE at reflux. However, PMB

protection with DCE gave low yields on most substrates. Toluene was then tested as the solvent

in hopes that heating the reaction to a higher temperature would improve reaction yields. Figure

2.11 shows PMB etherification of 1-octadecanol (2.34) at concentrations of 0.25 M, 0.5 M, and

1.0 M. Both reactions at concentrations of 0.5 M and 1.0 M gave high yields. PMB

etherifications were then performed in toluene at 1.0 M.

28

Figure 2.11: Concentration Studies

Cinnamyl alcohol is an interesting substrate because it is an allylic alcohol. Protection of

allylic alcohols have been previously reported in low yields with some PMB etherification

reagents,42 so they were chosen as a test of the methodology. Figure 2.12 shows a study of the

PMB etherification of cinnamyl alcohol under various conditions. The etherifications were

carried out at 1 M concentration and went for 24 hours unless otherwise noted. PMB protection

of cinnamyl alcohol in toluene only yielded 28% of the ether product. One possibility for the

low yield is that adventitious water was hydrolyzing the imidate, which led to the low yield.

Therefore, a series of drying reagents were tested in the PMB etherification. Molecular sieves,

barium oxide and magnesium oxide all led to decreased yield for the etherification.

Trichloroacetamide was also tested as a possible catalyst for the etherification but these

conditions gave comparable yield of PMB protected cinnamyl alcohol as observed with the neat

conditions.

29

Figure 2.12: PMB Etherification with Cinnamyl Alcohol

Since PMB protection of cinnamyl alcohol in toluene with various additives gave poor

results, a new solvent was tested. Toluene may be destroying the imidate through a Friedel-

Crafts process (although these products were never observed directly by 1H NMR), so a more

electron deficient solvent that was less likely to undergo Friedel-Crafts alkylation was utilized.

Therefore, α,α,α-trifluorotoluene was explored as the solvent (Figure 2.13). The etherification in

α,α,α-trifluorotoluene gave a 52% yield of the PMB protected cinnamyl alcohol. The

etherification was allowed to proceed for two days in hopes of a higher product yield but the

yield decreased to 32%. This may mean that shorter reaction times should be explored as a

means to increase the reaction yield, but first a number of other alcohol substrates were evaluated

at the 24 h time point (Table 2.5).

30

Figure 2.13: PMB Etherification with Cinnamyl Alcohol in α,α,α-Trifluorotoluene

Since α,α,α-trifluorotoluene provided the PMB protected cinnamyl alcohol in moderate

yield, α,α,α-trifluorotoluene was chosen as the solvent for substrate testing. The results of PMB

etherification in α,α,α-trifluorotoluene are shown in Table 2.5. Entries 1-4 demonstrate that the

methodology performs well with electron rich and electron poor benzyl alcohols. Propargyl

alcohol gave an 85% yield of its PMB ether; however, the tertiary propargyl alcohol yielded no

reaction product (entries 5-6). Other tertiary alcohols, like adamantyl alcohol, did provide some

product although the yields were more moderate than observed for the DPM imidate. Entry 8

demonstrates PMB etherification of an electron poor phenol works with a 76% yield. The

dihydrocholesterol derivative, a secondary alcohol, in entry 11 provided a 55% yield, which

again is lower than was observed for secondary alcohols in the case of the DPM imidate. Entries

9-10 and 12-16 are more complex examples that are acid and base sensitive. These examples

gave moderate to low yields demonstrating the PMB imidate is significantly less reactive than

the DPM imidate. Further studies on the reaction conditions or the use of a more reactive

imidate (like 2,4-dimethoxybenzyl or 2,6-dimethoxybenzyl) may be required to access a more

general system for the benzyl protection of alcohols.

31

Table 2.5: PMB Etherifications in α,α,α-Trifluorotoluene

Entry Product % Yield

1

81%

2

78%

3

85%

4

67%

5

85%

6

NR

7

40%

8

76%

9

33%

32

10

15%

11

55%

12 68%

13

58%

14

25%

15

61%

16

23%

PMB etherification was also performed on a number of diols (Table 2.6). The lower

reactivity of the PMB imidate may be beneficial in these cases, as higher selectivity may be

accessed for these systems. Entry 1 shows the mono PMB protected 1,4-butanediol in 59 %

yield. This yield is expected since in the presence of one equivalent of imidate a 2:1:1 mixture

of mono product: dialkylated product: starting material is predicted. Entry 2 is the dialkylated

product of 1,4-butanediol and was obtained in only a 41% yield. Primary alcohols can

selectively be protected in the presence of secondary and tertiary alcohols (entries 3, 4). Some

33

diols undergo monoprotection in much higher yields than could be anticipated a priori, for

example entries 5 and 6 were obtained in 80% and 79% yield respectively.

Table 2.6: PMB Etherification of Diols

Entry Product % Yield

1

59%a

2

41%b

3

34%a

4

68%a

5

80%a

6

79%a

7

36%a

a 1 eq. of PMB imidate was used.

b 3.3 eq. of PMB imidate were used.

The yield of the monoprotected product in these reactions is significantly higher than one

would predict based on statistical reactivity of the diols. The ability of these systems to form 5

34

and 6 membered hydrogen bonds (Figure 2.14) may explain this reactivity. One of the

hydrogens becomes more acidic when the diol is participating in this hydrogen bonding, leading

to the selective formation of the monoprotected ether. This intramolecular H-bonding is not

possible after monoprotection. The alkyne in entry 7 restricts that capability for hydrogen

bonding and therefore gave a lower yield of the monoprotected product (36%), further

supporting the role of hydrogen bonding in these systems.

Figure 2.14: Hydrogen bonding in diols

A one-pot PMB etherification from 4-methoxybenzyl alcohol was also attempted (Figure

2.15). In this procedure, the PMB imidate is generated in situ and not isolated. After the PMB

imidate is observed by TLC, 4-nitrobenzyl alcohol was added. This alcohol was chosen because

of its high reactivity in the PMB etherification. These experiments were performed in both

toluene and α,α,α-trifluorotoluene. The reaction in toluene only gave 15% yield of PMB

protected product while the reaction in α,α,α-trifluorotoluene gave 34% yield of product. These

poor yields may be due to the imidate forming in low yield in these solvents, as typically the

imidate formation is performed in diethyl ether.

35

Figure 2.15: One Pot PMB Etherification

Conclusions and Future Work

Thermal etherification was successful with both DPM and PMB imidate. Neutral,

thermal conditions do not require an acid or base catalyst for etherification. The DPM imidate

was found to be more reactive under these conditions, and therefore the method was more

general with regard to the alcohol substrates. This novel methodology allows for alcohol

protection on sensitive substrates. Chirality centers are also undisturbed when subjected to the

reaction conditions. Trichloroacetimidates were used to alkylate carboxylic acids and thiols as

well. Etherification using trichloroacetimidates under mild conditions will continue to be

explored. Further investigation using different substrates will be conducted. Etherification of

alcohols with other imidates will also be studied using similar, neutral conditions. Imidates with

more electron rich groups, such as 2,4- or 2,6-dimethoxybenzylimidate, will be tested to see if

reaction conditions and yields improve as compared to the 4-methoxybenzyl

trichloroacetimidate.

36

Experimental Procedures

General Information. All anhydrous reactions were run under a positive pressure of argon or

nitrogen. All syringes, needles, and reaction flasks required for anhydrous reactions were dried in

an oven and cooled under an N2 atmosphere or in a desiccator. DCM and THF were dried by

passage through an alumina column by the method of Grubbs.1 Triethylamine was distilled from

CaH2. All other reagents and solvents were purchased from commercial sources and used without

further purification.

Analysis and Purification. Analytical thin layer chromatography (TLC) was performed on

precoated glass backed plates (silica gel 60 F254; 0.25 mm thickness). The TLC plates were

visualized by UV illumination and by staining. Solvents for chromatography are listed as

volume:volume ratios. Flash column chromatography was carried out on silica gel (40-63 μm).

Melting points were recorded using an electrothermal melting point apparatus and are uncorrected.

Elemental analyses were performed on an elemental analyzer with a thermal conductivity detector

and 2 meter GC column maintained at 50 °C.

Identity. Proton (1H NMR) and carbon (13C NMR) nuclear magnetic resonance spectra were

recorded at 300 or 400 MHz and 75 or 100 MHz respectively. The chemical shifts are given in

parts per million (ppm) on the delta (δ) scale. Coupling constants are reported in hertz (Hz). The

spectra were recorded in solutions of deuterated chloroform (CDCl3), with residual chloroform (

7.26 ppm for 1H NMR, δ 77.23 ppm for 13C NMR) or tetramethylsilane ( 0.00 for 1H NMR,

0.00 for 13C NMR) as the internal reference. Data are reported as follows: (s = singlet; d = doublet;

t = triplet; q = quartet; p = pentet; sep = septet; dd = doublet of doublets; dt = doublet of triplets;

td = triplet of doublets; tt = triplet of triplets; qd = quartet of doublets; ddd = doublet of doublet of

doublets; br s = broad singlet). Where applicable, the number of protons attached to the

37

corresponding carbon atom was determined by DEPT 135 NMR. Infrared (IR) spectra were

obtained as thin films on NaCl plates by dissolving the compound in CH2Cl2 followed by

evaporation or as KBr pellets.

4-methoxybenzyl 3,3-dimethylbutanoate 2.5

In a flame dried 50 mL round bottom flask, tert-butylacetic acid (400 mg, 3.44 mmol) was

dissolved in dry dichloromethane (14 mL). 4-methoxybenzyl 2,2,2-trichloroacetimidate (1.934

g, 3.44 mmol) was added. The reaction was stirred at room temperature for 24 hours. The

reaction was taken up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times, dried

with sodium sulfate and concentrated. Purification was done with flash column chromatography

(10% ether/hexane) to give a clear oil (346 mg, 43%). TLC Rf = 0.58 (15% ethyl

acetate/hexanes); IR (neat) 2957, 2836, 1731, 1515 cm-1; 1H NMR (300 MHz, CDCl3): δ 7.30 (d,

J = 9.0 Hz, 2H), 6.89 (d, J = 8.6, 2H), 5.04 (s, 2H), 3.81 (s, 3H), 2.22 (s, 2H), 1.01 (s, 9H); 13C

NMR (75 MHz, CDCl3): δ 172.3, 159.7, 130.2, 128.5, 114.0, 65.8, 55.3, 48.1, 30.9, 29.8. Anal

calcd for C14H20O3: C, 71.16; H, 8.53. Found: C, 71.37; H, 8.37.

38

4-methoxybenzyl 2-methoxybenzoate 2.6

In a flame dried 50 mL round bottom flask, o-anisic acid (400 mg, 2.63 mmol) was dissolved in

dry dichloromethane (11 mL). 4-methoxybenzyl 2,2,2-trichloroacetimidate (1.486 g, 5.26 mmol)

was added. The reaction was stirred at room temperature for 24 hours. The reaction was taken

up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times, dried with sodium

sulfate and concentrated. Purification was done with flash column chromatography (10% ethyl

acetate/hexanes) to give a clear oil (433 mg, 60%). TLC Rf = 0.56 (25% ethyl acetate/hexanes);

IR (neat) 2956, 2837, 1724, 1514, 1245 cm-1; 1H NMR (300 MHz, CDCl3) δ 7.81 (d, J = 9.8 Hz,

1H), 7.37-7.47 (m, 3H), 6.89-6.97 (m, 4H), 5.29 (s, 2H), 3.88 (s, 3H), 3.79 (s, 3H); 13C NMR

(75 MHz, CDCl3) δ 166.0, 159.6, 159.4, 133.6, 131.7, 130.0, 128.4, 120.1, 113.9, 112.1, 66.4,

56.0, 55.3.

(E)-4-methoxybenzyl but-2-enoate 2.7

Lit. Ref.: Matsuo, J.; Kozai, T.; Ishibashi, H. Org. Lett. 2006, 8 (26), pp 6095–6098.

In a flame dried 50 mL round bottom flask, crotonic acid (400 mg, 4.65 mmol) was dissolved in

dry dichloromethane (19 mL). 4-methoxybenzyl 2,2,2-trichloroacetimidate (1.972 g, 6.98 mmol)

was added. The reaction was stirred at room temperature for 24 hours. The reaction was taken

up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times, dried with sodium

sulfate and concentrated. Purification was done with flash column chromatography (10% ethyl

acetate/hexanes) to give a clear oil (515 mg, 54%). TLC Rf = 0.25 (15% ethyl acetate/hexanes);

39

IR (neat) 3001, 2955, 2837, 1716, 1613, 1515, 1249 cm-1; 1H NMR (300 MHz, CDCl3) δ 7.31

(d, J = 8.7 Hz, 2H), 6.93-7.06 (m, 1H), 6.89 (d, J = 8.7 Hz, 2H), 5.87 (d, J = 15.0 Hz, 1H), 5.10

(s, 2H), 3.80 (s, 3H), 1.86 (d, J = 6.0 Hz, 3H); 13C NMR (75 MHz, CDCl3) δ 166.4, 159.7,

145.0, 130.1, 128.4, 122.7, 114.0, 65.8, 55.3, 18.0.

4-methoxybenzyl-1-adamantanoate 2.8

Lit. Ref.: Rolfe, A.; Loh, J. K.; Maity, P. K.; Hanson, P. R. Org. Lett. 2011, 13, 4-7.

In a flame dried 50 mL round bottom flask, 1-adamantanecarboxylic acid (400 mg, 2.22 mmol)

was dissolved in dry dichloromethane (9 mL). 4-methoxybenzyl 2,2,2-trichloroacetimidate

(1.255 g, 4.44 mmol) was added. The reaction was stirred at room temperature for 24 hours.

The reaction was taken up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times,

dried with sodium sulfate and concentrated. Purification was done with flash column

chromatography (10% ether/hexanes) to give a clear oil (426 mg, 64%). TLC Rf = 0.65 (25%

ethyl acetate/hexanes); IR (neat) 2999, 2906, 2851, 1724, 1514, 1229 cm-1; 1H NMR (300 MHz,

CDCl3) δ 7.27 (d, J = 8.6 Hz, 2H), 6.88 (d, J = 8.7 Hz, 2H), 5.03 (s, 2H), 3.81 (s, 3H), 1.71-2.00

(m, 15H); 13C NMR (75 MHz, CDCl3) δ 177.6, 159.5, 129.6, 128.8, 113.9, 65.7, 55.3, 40.8,

38.9, 36.6, 28.1.

40

(S)-4-methoxybenzyl 3,3,3-trifluoro-2-methoxy-2-phenylpropanoate 2.9

Lit. Ref.: Yamada, I.; Noyori, R. Organic Letters, 2000, 2, 3425 – 3427.

In a flame dried 10 mL round bottom flask, (S)-(-)-α-(trifluoromethyl)phenylactic acid (50 mg,

0.214 mmol) was dissolved in dry dichloromethane (1 mL). 4-methoxybenzyl 2,2,2-

trichloroacetimidate (12 mg, 0.428 mmol) was added. The reaction was stirred at room

temperature overnight. The reaction was taken up in ethyl acetate, washed with sat. aq. sodium

bicarbonate three times, dried with sodium sulfate and concentrated. Purification was done with

flash column chromatography (10% ether/hexanes) to give a clear oil (38 mg, 50%). TLC Rf =

0.36 (25% ethyl acetate/hexanes); IR (neat) 2954, 2841, 1747, 1516, 1248, 1174 cm-1; 1H NMR

(300 MHz, CDCl3) δ 7.26-7.46 (m, 6H), 6.88 (d, J = 8.7 Hz, 2H), 5.29 (q, J = 11.8 Hz, 2H), 3.81

(s, 3H), 3.51 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 166.5, 160.0, 132.3, 130.5, 129.6, 128.4,

127.3, 126.8, 125.2, 121.4, 114.0, 67.9, 55.5, 55.3.

4-methoxybenzyl 2,2-diphenylacetate 2.10

In a flame dried 50 mL round bottom flask, diphenylacetic acid (400 mg, 1.88 mmol) was

dissolved in dry dichloromethane (8 mL). 4-methoxybenzyl 2,2,2-trichloroacetimidate (1.062 g,

41

3.76 mmol) was added. The reaction was stirred at room temperature for 24 hours. The reaction

was taken up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times, dried with

sodium sulfate and concentrated. Purification was done with flash column chromatography

(10% ethyl acetate/hexanes) to give an orange solid (394 mg, 63%). TLC Rf = 0.35 (25% ethyl

acetate/hexanes); IR (KBr) 3028, 2956, 2836, 1734, 1612, 1514, 1250, 1145 cm-1; 1H NMR (300

MHz, CDCl3) δ 7.26-7.34 (m, 11H), 6.90 (d, J = 8.6 Hz, 2H), 5.17 (s, 2H), 5.09 (s, 1H), 3.84 (s,

3H); 13C NMR (75 MHz, CDCl3) δ 172.5, 159.8, 138.8, 130.2, 128.8, 128.7, 127.9, 127.4,

114.0, 66.9, 57.2, 55.4.

4-methoxybenzyl 2-acetoxybenzoate 2.11

In a flame dried 50 mL round bottom flask, acetylsalicylic acid (400 mg, 2.22 mmol) was

dissolved in dry dichloromethane (9 mL). 4-methoxybenzyl 2,2,2-trichloroacetimidate (1.255 g,

4.44 mmol) was added. The reaction was stirred at room temperature for 24 hours. The reaction

was taken up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times, dried with

sodium sulfate and concentrated. Purification was done with flash column chromatography

(10% ethyl acetate/hexanes) to give a clear oil (534 mg, 80%). TLC Rf = 0.69 (25% ethyl

acetate/hexanes); IR (neat) 2957, 2837, 1769, 1720, 1610, 1515, 1248 1195 cm-1; 1H NMR (300

MHz, CDCl3) δ 8.04 (d, J = 1.7 Hz, 1H), 7.54 (t, J = 9.0 Hz, 1H), 7.29-7.38 (m, 3H), 7.09 (d, J =

9.0 Hz, 1H), 6.92 (d, J = 8.7 Hz, 2H), 5.24 (s, 2H), 3.81 (s, 3H), 2.13 (s, 3H); 13C NMR (75

MHz, CDCl3) δ 169.8, 164.6, 159.9, 150.7, 133.2, 132.1, 130.5, 127.7, 126.1, 123.9, 123.5,

114.3, 67.0, 55.4, 20.8. Anal calcd for C17H16O5: C, 67.99; H, 5.37. Found: C, 67.60; H, 5.17.

42

4-methoxybenzyl cyclopropanecarboxylate 2.12

In a flame dried 50 mL round bottom flask, cyclopropane carboxylic acid (400 mg, 4.65 mmol)

was dissolved in dry dichloromethane (19 mL). 4-methoxybenzyl 2,2,2-trichloroacetimidate

(1.600 g, 5.66 mmol) was added. The reaction was stirred at room temperature for 24 hours.

The reaction was taken up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times,

dried with sodium sulfate and concentrated. Purification was done with flash column

chromatography (10% ethyl acetate/hexanes) to give a clear oil (493 mg, 51%). TLC Rf = 0.53

(25% ethyl acetate/hexanes); IR (neat) 3011, 2956, 2836, 1724, 1613, 1515, 1249, 1166 cm-1; 1H

NMR (300 MHz, CDCl3) δ 7.30 (d, J= 8.6 Hz, 2H), 6.88 (d, J= 8.7 Hz, 2H), 5.05 (s, 2H), 3.78 (s,

3H), 1.59-1.67 (m, 1H), 0.94-1.08 (m, 2H), 0.78-0.91 (m, 2H); 13C NMR (75 MHz, CDCl3) δ

174.7, 159.6, 130.1, 128.3, 113.9, 66.1, 55.2, 13.0, 8.5.

4-methoxybenzyl 3-(2,4-dichlorobenzyloxy)thiophene-2-carboxylate 2.13

In a flame dried 50 mL round bottom flask, 3-(2,4-dichlorobenzyloxy)thiophene-2-carboxylic

acid (400 mg, 1.32 mmol) was dissolved in dry dichloromethane (3 mL). 4-methoxybenzyl

2,2,2-trichloroacetimidate (746 mg, 2.64 mmol) was dissolved in dry dichloromethane (3 mL)

and added to the round bottom flask. The reaction was stirred at room temperature for 24 hours.

43

The reaction was taken up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times,

dried with sodium sulfate and concentrated. Purification was done with flash column

chromatography (10% ethyl acetate/hexanes) to give a white solid (153 mg, 27%). mp = ; TLC

Rf = 0.58 (25% ethyl acetate/hexanes); IR (neat) 2954, 1682, 1588, 1544, 1431, 1384, 1248 cm-1;

1H NMR (300 MHz, CDCl3) δ 7.53 (d, J = 8.4 Hz, 1H), 7.34-7.43 (m, 3H), 7.15 (d, J = 6.0 Hz,

1H), 6.89-6.92 (m, 3H), 5.30 (s, 2H), 5.71 (s, 2H), 3.81 (s, 3H).

4-methoxybenzyl 2-(diphenylphosphino)benzoate 2.14

In a flame dried 50 mL round bottom flask, 2-(diphenylphosphino)benzoic acid (400 mg, 1.31

mmol) was dissolved in dry dichloromethane (2.5 mL). 4-methoxybenzyl 2,2,2-

trichloroacetimidate (746 mg, 2.64 mmol) was dissolved in dry dichloromethane (2.5 mL) and

added to the round bottom flask. The reaction was stirred at room temperature for 24 hours. The

reaction was taken up in ethyl acetate, washed with sat. aq. sodium bicarbonate three times, dried

with sodium sulfate and concentrated. Purification was done with flash column chromatography

(1:1 ethyl acetate/hexanes) to give a clear oil (139 mg, 25%). TLC Rf = 0.26 (60% ethyl

acetate/hexanes); IR (neat) 3056, 1727, 1612, 1514, 1248, 1118 cm-1; 1H NMR (300 MHz,

CDCl3) δ 7.86-7.90 (m, 1H), 7.39-7.68 (m, 13H), 7.07 (d, J = 14.2 Hz, 2H), 6.78 (d, J = 9.0, 2H),

4.90 (s, 2H), 3.78 (s, 3H).

44

O

OH

O CCl3

NH

DCM, 24 h92%

O

O

benzhydryl 3,3-dimethylbutanoate 2.17

In a flame dried 50 mL round bottom flask, tert-butylacetic acid (0.33 mL, 2.58 mmol) was

dissolved in dry dichloromethane (10 mL). Benzhydryl 2,2,2-trichloroacetimidate (1.101 g, 3.35

mmol) was added. The reaction was stirred at room temperature for 24 hours. The reaction was

concentrated. Purification was done with flash column chromatography (1% ethyl

acetate/hexanes) to give a clear oil (0.669 g, 92%). TLC Rf = 0.79 (10% ethyl acetate/hexanes);

1H NMR (300 MHz, CDCl3): δ 7.26-7.37 (m, 9H), 6.89 (s, 1H), 2.32 (s, 2H), 0.99 (s, 9H); 13C

NMR (75 MHz, CDCl3): δ 171.4, 140.6, 128.6, 127.9, 127.4, 76.7, 48.2, 31.1, 29.8. Anal. Calcd

for C19H22O2: C, 80.82; H, 7.85. Found: C, 81.11; H, 8.03.

benzhydryl-1-adamantanoate 2.19

In a flame dried 25 mL round bottom flask, adamantane-1-carboxylic acid (0.300 g, 1.66 mmol)

was dissolved in dry dichloromethane (7 mL). Benzhydryl 2,2,2-trichloroacetimidate (0.710 g,

2.16 mmol) was added. The reaction was stirred at room temperature for 24 hours. The reaction

was concentrated. Purification was done with flash column chromatography (1% ethyl

acetate/hexanes) to give an orange solid (0.177 g, 31%). TLC Rf = 0.64 (10% ethyl

acetate/hexanes); 1H NMR (300 MHz, CDCl3) δ 7.23-7.36 (m, 16H), 6.83 (s, 1H), 2.03 (bs, 4H),

45

1.96 (bs, 9H), 1.73 (bs, 9H); 13C NMR (75 MHz, CDCl3) δ 176.5, 142.4, 140.9, 128.6, 128.5,

127.9, 127.6, 127.4, 127.1, 80.1, 76.3, 40.9, 39.0, 36.7, 28.1. Anal. Calcd for C24H26O2: C,

83.20; H, 7.56. Found: C, 83.17; H, 7.85.

General Procedure for Forming Sulfides from Trichloroacetimidates:

The thiol was placed in a dry round bottom flask and dissolved in anhydrous THF (or toluene) to

a concentration of 0.2 M. The trichloroacetimidate (1.2 equiv) was then added and the reaction

was warmed to reflux. After 18 hours the reaction was cooled to room temperature and

concentrated under reduced pressure. The residue was then pre-adsorbed on silica gel and

purified by column chromatography. Alternatively, the residue can be dissolved in ethyl acetate,

washed with 2M aq. NaOH (3x), dried (Na2SO4) and concentrated (this workup removes the

trichloroacetamide byproduct). For some sulfides this workup provided analytically pure

material, in others the residue is purified by silica gel chromatography to provide the pure sulfide

product.

5-[(3-Methyl-2-butenyl)thio]-1-phenyl-1H-tetrazole 2.21.

Cream colored solid (0.250 g, 98%). mp =38.6-39.9°C; TLC Rf = 0.72 (30% ethyl acetate /70%

hexanes); IR (neat) 3062, 3015, 2981, 2928, 2895 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.61-7.55

(m, 5H), 5.44-7.37 (m, 1H), 4.04 (d, J = 8.0 Hz, 2H), 1.73 (s, 6H) . Anal calcd for C12H14N4S: C,

58.51; H, 5.73, N, 22.74. Found: C, 58.29; H, 5.54; N, 22.39.

46

1-Phenyl-5-[[(2E)-3-phenyl-2-propen-1-yl]thio]-1H-tetrazole 2.22.

Lit. Ref.: Han, X.; Wu, J. Org. Lett. 2010, 12, 5780-5782.

Yellow oil (0.264 g, 95%). TLC Rf = 0.63 (30% ethyl acetate /70% hexanes); 1H NMR (400

MHz, CDCl3) δ 7.61-7.55 (m, 5H), 7.39- 7.27 (m, 5H), 6.72 (d, J = 15.6 Hz, 1H), 6.41-6.31 (m,

1H), 4.23 (d, J = 8.8 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 153.9, 136.2, 135.4, 133.8, 130.3,

130.0, 128.8, 128.3, 126.7, 124.0, 122.6, 36.1.

5-(Isopropylthio)-1-phenyl-1H-tetrazole 2.23.

Lit. Ref.: Marti, C.; Carreira, E. M. J. Am. Chem. Soc. 2005, 127, 11505-11515.

Yellow oil (0.689 g, 38%). TLC Rf = 0.64 (35% DCM /65% hexanes); 1H NMR (400 MHz,

CDCl3) δ 7.58-7.52 (m, 5H), 3.42 (heptet, J = 6.5 Hz, 1H), 1.51 (d, J = 6.5 Hz, 6H); 13C NMR

(75 MHz, CDCl3) δ 154.1, 133.7, 130.1, 129.7, 124.0, 39.8, 23.3.

General Procedure for the Formation of DPM Ethers from Alcohols under Thermal

Conditions:

The alcohol was placed in a 25 mL flame dried round bottom flask and dissolved in anhydrous

toluene to a concentration of 0.25 M. The trichloroacetimidate (1.2 equiv) was added and the

reaction warmed to reflux. After 18 hours, the reaction was cooled to room temperature and

concentrated under reduced pressure. The residue was pre-adsorbed on silica gel and purified by

silica gel column chromatography. The residue can be dissolved in ethyl acetate, washed with

2M aq. NaOH (3x), dried (Na2SO4) and concentrated (this workup removes the

trichloroacetamide byproduct).

47

Octadecyloxydiphenylmethane 2.35.

White solid (0.273 g, 85%). mp = 47-48 °C; TLC Rf = 0.80 (10% ethyl acetate/hexanes); IR (solid

film from CH2Cl2) 3027, 2923, 2852, 1493, 1453, 1097 cm-1; 1H NMR (300 MHz, CDCl3) δ 7.21-

7.37 (m, 10H), 5.33 (s, 1H), 3.44 (t, J = 6.6 Hz, 2H), 1.60-1.67 (m, 2H), 1.26 (m, 30H), 0.88 (t, J

= 6.3 Hz, 3H); 13C NMR (75 MHz, CDCl3) δ 142.9, 128.5, 127.5, 127.2, 83.8, 69.4, 32.2, 30.1,

29.94, 29.91, 29.87, 29.85, 29.7, 29.6, 26.5, 22.9, 14.3 (several signals in the aliphatic region were

not resolved). Anal calcd for C31H48O: C, 85.26; H, 11.08. Found: C, 85.18; H, 11.13.

Benzyloxydiphenylmethane 2.36.

Lit. Ref.: Xu, Q.; Xie, H.; Chen, P.; Yu, L.; Chen, J.; Hu, X. Green Chem. 2015, 17, 2774-2779.

Clear oil (0.238 g, 94%). TLC Rf = 0.92 (25% ethyl acetate/hexanes); 1H NMR (300 MHz, CDCl3)

δ 7.24-7.42 (m, 15H), 5.46 (s, 1H), 4.56 (s, 2H); 13C NMR (75 MHz, CDCl3) δ 142.4, 138.6, 128.6,

128.6, 127.9, 127.72, 127.65, 127.3, 82.7, 70.7.

48

(4-Methoxybenzyloxy)diphenylmethane 2.37.

Lit. Ref.: Kalutharage, N.; Yi, C. S. Org. Lett. 2015, 17, 1778-1781.

Clear oil (0.314 g, 71%). TLC Rf = 0.50 (10% ethyl acetate/hexanes); 1H NMR (300 MHz, CDCl3)

δ 7.24-7.41 (m, 12H), 6.91 (d, J = 8.7 Hz, 2H), 5.45 (s, 1H), 4.50 (s, 2H), 3.83 (s, 3H); 13C NMR

(100 MHz, CDCl3) δ 159.3, 142.4, 130.6, 129.5, 128.5, 127.6, 127.3, 113.9, 82.2, 70.3, 55.4.

(((4-Nitrobenzyl)oxy)methylene)dibenzene 2.39.

Off-white solid (0.460 g, 88%). mp = 62-64 °C (DCM); TLC Rf = 0.59 (40% DCM/60% hexanes);

IR (solid film from CH2Cl2) 3062, 3028, 2922, 2857, 1493, 1347, 1288 cm-1; 1H NMR (300 MHz,

CDCl3) δ 8.19 (d, J = 8.7 Hz, 2H), 7.52 (d, J = 8.1 Hz, 2H), 7.25-7.40 (m, 10H), 5.46 (s, 1H), 4.62

(s, 2H); 13C NMR (75 MHz, CDCl3) δ 147.4, 146.1, 141.6, 128.6, 127.8, 127.7, 127.0, 123.6, 83.5,

69.5. Anal calcd for C20H17NO3: C, 77.22; H, 5.37; N, 3.49. Found: C, 77.20; H, 5.31; N, 3.44.

Cinnamyloxydiphenylmethane 2.43.

Lit. Ref.: Zhang, W.; Haight, A. R.; Hsu, M. C. Tetrahedron Lett. 2002, 43, 6575-6578.

49

White solid (0.395 g, 88%). mp = 55-57 °C; TLC Rf = 0.58 (25% ethyl acetate/hexanes); 1H NMR

(300 MHz, CDCl3) δ 7.23-7.42 (m, 15H), 6.63 (d, J = 15.9 Hz, 1H), 6.32-6.41 (m, 1H), 5.51 (s,

1H), 4.20 (dd, J = 6.0, 1.5 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 142.3, 136.9, 132.3, 128.6,

128.5, 127.7, 127.5, 127.1, 126.6, 126.3, 82.8, 69.4.

Diphenyl(prop-2-ynyloxy)methane 2.47.

Lit. Ref.: Louvel, J.; Carvalho, J. F. S.; Yu, Z.; Soethoudt, M.; Lenselink, E. B.; Klaasse, E.;

Brussee, J.; Ijzerman, A. P. J. Med. Chem. 2013, 56, 9427-9440.

Yellow oil (0.384 g, 97%). TLC Rf = 0.86 (10% ethyl acetate/hexanes); 1H NMR (300 MHz,

CDCl3) δ 7.24-7.40 (m, 10H), 5.68 (s, 1H), 4.17 (d, J = 2.4 Hz, 2H), 2.46 (t, J = 2.4 Hz, 1H); 13C

NMR (100 MHz, CDCl3) δ 141.3, 128.6, 127.9, 127.5, 81.8, 79.9, 74.8, 56.0.

((Cyclohexyloxy)methylene)dibenzene 2.44.

Lit. Ref.: Bhaskar, G.; Solomon, M.; Babu, G.; Muralidharan, D.; Perumal, P. T. Indian J.

Chem., Sect. B. 2010, 49B, 795-801.

Clear oil (0.494 g, 93%). TLC Rf = 0.68 (10% ethyl acetate/hexanes); 1H NMR (300 MHz, CDCl3)

δ 7.24-7.40 (m, 10H), 5.58 (s, 1H), 3.35-3.44 (m, 1H), 1.93 (dd, J = 9.0, 6.0 Hz, 2H), 1.76-1.82

50

(m, 2H), 1.41-1.58 (m, 3H), 1.26 (q, J = 8.3 Hz, 3H); 13C NMR (75MHz, CDCl3) δ143.3, 128.4,

127.31, 127.26, 80.1, 75.1, 32.5, 26.0, 24.2.

((1-Phenylethoxy)methylene)dibenzene 2.38.

Lit. Ref.: Sciebura, J.; Gawronski, J. Tetrahedron: Asymmetry 2013, 24, 683-688.

Clear oil (0.434 g, 92%). TLC Rf = 0.85 (10% acetone/hexanes); 1H NMR (300 MHz, CDCl3) δ

7.20-7.41 (m, 15H), 5.31 (s, 1H), 4.51 (q, J = 6.6 Hz, 1H), 1.53 (d, J = 6.3 Hz, 3H); 13C NMR (75

MHz, CDCl3) δ 143.9, 143.0, 142.2, 128.7, 128.4, 128.3, 127.73, 127.70, 127.67, 127.3, 127.1,

126.7, 80.2, 75.1, 24.5.

((tert-Pentyloxy)methylene)dibenzene 2.45.

Lit. Ref.: Buckley, A.; Chapman, N. B.; Dack, M. R. J.; Shorter, J.; Wall, H. M. J. Chem. Soc., B

1968, 631-638.

Clear oil (0.489 g, 85%). TLC Rf = 0.92 (10% ethyl acetate/hexanes); 1H NMR (300 MHz, CDCl3)

δ 7.41 (d, J = 6.9 Hz, 4H), 7.33 (t, J = 7.2 Hz, 4H), 7.20-7.26 (m, 2H), 5.60 (s, 1H), 1.62 (q, J =

7.5 Hz, 2H), 1.17 (s, 6H), 0.91 (t, J = 7.5 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 145.6, 128.3,

127.0, 126.9, 76.9, 75.6, 34.8, 26.1, 8.9.

51

1-(Benzhydryloxy)adamantane 2.46.

Orange solid (0.383 g, 92%). mp = 64-66 °C; TLC Rf = 0.71 (10% ethyl acetate/hexanes); IR (solid

film from CH2Cl2) 3025, 2905, 2850, 1492, 1451, 1354, 1082 cm-1; 1H NMR (300 MHz, CDCl3)

δ 7.20-7.39 (m, 10H), 5.80 (s, 1H), 2.14 (s, 3H), 1.83 (bs, 6H), 1.62 (bs, 6H); 13C NMR (100 MHz,

CDCl3) δ 145.3, 128.2, 127.2, 126.9, 74.4, 73.8, 43.0, 36.6, 30.8. Anal calcd for C23H26O: C, 86.75;

H, 8.23. Found: C, 86.72; H, 8.18.

2-((Benzhydryloxy)methyl)-3-phenyloxirane 2.51.

Lit. Ref.: Vidal-Ferran, A.; Moyano, A.; Pericas, M. A.; Riera, A. J. Org. Chem. 1997, 62, 4970-

4982.

Clear oil (0.255 g, 65%) TLC Rf = 0.50 (10% ethyl acetate/hexanes); 1H NMR (300 MHz, CDCl3)

δ 7.25-7.44 (m, 15H), 5.53 (s, 1H), 3.86 (dd, J = 11.5, 3.1 Hz, 1H), 3.80 (d, J = 2.0 Hz, 1H) 3.66

(dd, J = 5.3, 11.5 Hz, 1H), 3.29-3.32 (m, 1H). 13C NMR (100 MHz, CDCl3) δ 141.99, 141.94,

137.1, 128.7, 128.6, 128.4, 127.8, 127.77, 127.5, 127.3, 127.2, 125.9, 84.1, 68.9, 61.4, 56.1.

52

(2-(Benzhydryloxy)ethyl)trimethylsilane 2.53.

Pale yellow oil (0.368 g, 79%). TLC Rf = 0.56 (15% DCM/5% triethylamine/ 80% hexanes); IR

(solid film from CH2Cl2) 3087, 3063, 3029, 2953, 2892, 1452, 1317, 1249 cm-1; 1H NMR (400

MHz, CDCl3) δ 7.36 (dd, J = 6.3, 1.2 Hz, 4H), 7.30 (t, J = 6.6 Hz, 4H), 7.22-7.25 (m, 2H), 5.35 (s,

1H), 3.56 (t, J = 6.0 Hz, 2H), 1.03 (t, J = 6.0 Hz, 2H), 0.00 (s, 9H); 13C NMR (100 MHz, CDCl3)

δ 144.0, 129.6, 128.5, 128.2, 84.6, 67.6, 19.7, 0.0; Anal calcd for C18H24OSi: C, 76.00; H, 8.50;

Found: C, 75.77; H, 8.62.

2-(Benzhydryloxy)isoindoline-1,3-dione 2.49.

Lit. Ref.: Reddy, C. R.; Radhika, L.; Kumar, T. P.; Chandrasekhar, S. Eur. J. Org. Chem. 2011,

2011, 5967-5970.

Yellow solid (0.323 g, 80%). mp = 160-162 °C; TLC Rf = 0.29 (10% acetone/hexanes); 1H NMR

(300 MHz, CDCl3) δ 7.66-7.76 (m, 4H), 7.52-7.56 (m, 4H), 7.29-7.39 (m, 6H), 6.53 (s, 1H); 13C

NMR (100 MHz, CDCl3) δ 163.8, 137.9, 134.4, 128.9, 128.8, 128.5, 128.4, 123.4, 89.7.

53

(S)-Benzyl 3-(benzhydryloxy)-2-(((benzyloxy)carbonyl)amino)propanoate 2.55.

Clear oil (0.273 g, 91%). [α]𝐷21.6 -12.5 (c 1.26, CHCl3); TLC Rf = 0.18 (10% ethyl acetate/hexanes);

IR (solid film from CH2Cl2) 3434, 3341, 3062, 3030, 2949, 2876, 1722, 1498, 1339, 1197, 1067

cm-1; 1H NMR (400 MHz, CDCl3) δ 7.07-7.30 (m, 20H), 5.63 (d, J = 12.0 Hz, 1H), 5.19 (s, 1H),

5.12 (d, J = 4.0 Hz, 2H), 5.04 (s, 2H), 4.49 (dt, J = 2.8 Hz, 1H), 3.84 (dd, J = 9.4, 2.8 Hz, 1H),

3.60 (dd, J = 9.4, 3.1 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ170.3, 156.1, 141.6, 141.4, 136.4,

135.4, 128.7, 128.65, 128.6, 128.5, 128.4, 128.3, 128.2, 127.7, 127.0, 126.9, 84.2, 69.0, 67.4, 67.2,

54.8 . (note: two signals in the aromatic region were not resolved.) Anal calcd for C31H29NO5: C,

75.13; H, 5.90; N, 2.83. Found: C, 74.94; H, 5.97; N, 3.00. Chiral HPLC analysis: Chiralcel OD

(heptane/2-PrOH = 90/10, 1.0 mL/min, 254 nm, 25 °C): t(S enantiomer) = 16.7 min, t(R enantiomer) = 23.9

min.

Methyl 2,3,4-Tri-O-benzyl-6-O-diphenylmethyl-α-D-glucopyranoside 2.52.

Lit. Ref.: Ali, I. A. I.; El Ashry, E. S. H.; Schmidt, R. R. Eur. J. Org. Chem. 2003, 4121-4131.

Clear colored oil (0.750 g, 73%). TLC Rf = 0.43 (15% ethyl acetate/85% hexanes); 1H NMR (300

MHz, CDCl3) δ 7.55-7.18 (m, 25 H), 5.50 (s, 1H), 5.13 (d, J = 10.8 Hz, 1H), 4.98 (t, J = 11.1 Hz,

54

2H), 4.93 (d, J = 12.0 Hz, 1H), 4.82 (d, J = 11.7 Hz, 1H), 4.80 (d, J = 3.6 Hz, 1H), 4.68 (d, J =

11.1 Hz, 1H), 4.16 (t, J = 9.3 Hz, 1H), 3.89-3.99 (m, 1H), 3.77-3.84 (m, 3H), 3.72 (dd, J = 3.6,

9.6 Hz, 1H), 3.49 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 142.2, 142.1, 138.8, 138.3, 138.2, 128.5,

128.4, 128.36, 128.1, 127.9, 127.8, 127.7, 127.5, 127.4, 127.2, 126.9, 98.1, 84.1, 82.3, 80.1, 78.0,

75.9, 75.1, 73.4, 70.3, 67.9, 55.1.

(3S,5S,8R,9S,10S,13R,14S,17R)-3-(Benzhydryloxy)-10,13-dimethyl-17-((R)-6-

methylheptan-2-yl)hexadecahydro-1H-cyclopenta[a]phenanthrene 2.48.

White solid (0.374 g, 87%). [α]𝐷21.6 +12.4 (c 1.04, CHCl3); mp = 127-129 °C; TLC Rf = 0.74 (10%

ethyl acetate/hexanes); IR (solid film from CH2Cl2) 3027, 2930, 2865, 1493, 1452, 1381, 1062 cm-

1; 1H NMR (300 MHz, CDCl3) δ 7.16-7.34 (m, 10H), 5.54 (s, 1H), 3.28-3.38 (m, 1H), 0.63-1.92

(m, 46H); 13C NMR (75 MHz, CDCl3) δ 143.3, 128.4, 127.4, 127.3, 80.3, 76.5, 56.7, 56.5, 54.6,

45.0, 42.8, 40.3, 39.7, 37.2, 36.4, 36.0, 35.95, 35.7, 35.3, 32.3, 29.1, 28.7, 28.5, 28.2, 24.4, 24.0,

23.0, 22.8, 21.4, 18.9, 12.5, 12.3. Anal calcd for C40H58O: C, 86.58; H, 10.54. Found: C, 86.59; H,

10.68.

55

Ethyl 3-(benzhydryloxy)-3-phenylpropanoate 2.50.

White solid (0.178 g, 96%). mp = 73-74 °C; TLC Rf = 0.53 (10% ethyl acetate/hexanes); IR (solid

film from CH2Cl2) 3061, 3028, 2980, 1736, 1493, 1453, 1268, 1172, 1052 cm-1; 1H NMR (300

MHz, CDCl3) δ 7.19-7.40 (m, 15H), 5.24 (s, 1H), 4.81 (ddd, J = 1.3, 4.9, 9.0 Hz, 1H), 4.00-4.23

(m, 2H), 2.96 (ddd, J = 1.4, 9.0, 14.7 Hz, 1H), 2.65 (ddd, J = 1.2, 4.9, 14.7 Hz, 1H), 1.21 (td, J =

1.1, 7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 170.8, 142.8, 141.3, 140.7, 128.8, 128.6, 128.3,

128.2, 128.0, 127.9, 127.24, 127.16 126.7, 80.11, 75.7, 60.6, 44.0, 14.3. Anal calcd for C24H24O3:

C, 79.97; H, 6.71. Found: C, 79.96; H, 6.88.

(R)-Ethyl 2-(benzhydryloxy)propanoate 2.54.

Lit. Ref.: Steinbeck, M.; Frey, G. D.; Schoeller, W. W.; Herrmann, W. A. J. Organomet. Chem.

2011, 696, 3945-3954.

Clear oil (0.434 g, 90%). [α]𝐷21.6 -103.8 (c 1.04, DCM); TLC Rf = 0.57 (10% ethyl

acetate/hexanes); 1H NMR (300 MHz, CDCl3) δ 7.26-7.41 (m, 10H), 5.57 (s, 1H), 4.16-4.28 (m,

2H), 4.08 (q, J = 6.0 Hz, 1H), 1.49 (d, J = 9.0 Hz, 3H), 1.30 (t, J = 9.0 Hz, 3H); 13C NMR (100

MHz, CDCl3) δ 173.6, 142.1, 141.1, 128.7, 128.4, 128.0, 127.7, 127.6, 127.5, 82.8, 72.7, 61.0,

56

19.0, 14.4. Chiral HPLC analysis: Chiralcel OD (heptane/2-PrOH = 99/1, 1.0 mL/min, 254 nm, 25

°C): t(R enantiomer) = 5.3 min, t(S enantiomer) = 5.8 min.

((4-Methoxyphenoxy)methylene)dibenzene 2.40.

Lit. Ref.: Bordwell, F. G.; Harrelson, J. A., Jr. J. Org. Chem. 1989, 54, 4893-4898.

Orange solid (0.424 g, 91%). mp = 84-85 °C; TLC Rf = 0.42 (10% acetone/hexanes); 1H NMR

(300 MHz, CDCl3) δ 7.26-7.43 (m, 10H), 6.88 (d, J = 9.1 Hz, 2H), 6.75 (d, J = 9.2 Hz, 2H), 6.11

(s, 1H), 3.73 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 154.2, 152.4, 141.7, 128.7, 127.8, 127.1,

117.4, 114.7, 82.8, 55.7.

((4-Nitrophenoxy)methylene)dibenzene 2.41.

Lit. Ref.: Maslak, P.; Guthrie, R. D. J. Am. Chem. Soc. 1986, 108, 2628-2636.

Pale yellow colored solid (0.310 g, 61%). mp = 157-158 °C; TLC Rf = 0.36 (10% ethyl acetate/90%

hexanes); 1H NMR (300 MHz, CDCl3) δ 8.13 (d, J = 9.0 Hz, 2H), 7.28-7.42 (m, 10H), 7.02 (d, J

= 9.3 Hz, 2H), 6.31 (s, 1H); 13C NMR (75 MHz, CDCl3) δ 162.9, 141.6, 139.8, 128.8, 128.3, 126.7,

125.8, 115.9, 82.5.

57

Methyl 3-(benzhydryloxy)thiophene-2-carboxylate 2.42.

White solid, (0.280 g, 53%). mp = 105-106 °C; TLC Rf = 0.3 (10% ethyl acetate/90% hexanes);

IR (solid film from CH2Cl2) 3061, 3028, 2948, 1711, 1538, 1228, 1062 cm-1; 1H NMR (400 MHz,

CDCl3) δ 7.53 (d, J = 7.6 Hz, 4H), 7.35 (t, J = 7.2 Hz, 4H), 7.25–7.28 (m, 3H), 6.74 (d, J = 5.6 Hz,

1H), 6.27 (s, 1H), 3.90 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 162.4, 160.1, 141.2, 130.4, 128.9,

128.1, 126.7, 118.7, 111.6, 85.0, 51.8. Anal calcd for C19H16O3S: C, 70.35; H, 4.97; Found: C,

70.26; H, 5.02.

1-methoxy-4-((1-phenylethoxy)methyl)benzene 2.66

Lit. Ref.: Bartels, B.; Hunter, R. J. Org. Chem., 1993, 58, 6756–6765.

In a 10 mL flame dried round bottom flask, 1-phenylethanol (0.366 g, 3.0 mmol) was dissolved

in anhydrous trifluorotoluene (3 mL). PMB imidate (1.690g, 6.0 mmol) was added to the flask.

The reaction refluxed for 20 hours. The reaction was concentrated. Purification was done using

column chromatography (10% ethyl acetate/hexanes) followed by column chromatography (50%

CH2Cl2) to give product as a clear colorless oil (0.477 g, 67%).

TLC Rf = 0.52 (10% ethyl acetate/90% hexanes); 1H NMR (300 MHz, CDCl3) δ 7.35-7.20 (m,

6H), 6.85 (d, J = 8.7 Hz, 2H), 4.46 (q, J = 6.6 Hz, 1H), 4.23 (dd, J = 11.4, 46.8 Hz, 2H), 3.75 (s,

3H), 1.45 (d, J = 6.3 Hz, 3H); 13C NMR (75 MHz, CDCl3) δ 159.2, 143.9, 130.8, 129.4, 128.6,

127.5, 126.4, 113.9, 77.0, 55.3, 24.3;

58

4-methoxybenzyl benzyl ether 2.63.

Lit. Ref.: Baltzly, R.; Buck, J. S. J. Am. Chem. Soc., 1943, 65, 1984–1992

81% yield, clear colored oil. TLC Rf = 0.54 (20% ethyl acetate/80% hexanes); 1H NMR (400

MHz, CDCl3) δ 7.34-7.23 (m, 7 H), 6.87 (d, J = 8.4 Hz, 2 H), 4.51 (s, 2 H), 4.48 (s, 2 H), 3.77 (s,

3 H); 13C NMR (100 MHz, CDCl3) δ 159.1, 138.3, 130.3, 129.3, 128.3, 127.7, 127.5, 113.7,

71.6, 55.2.

bis(4-methoxybenzyl)ether 2.64.

Lit. Ref.: Felix, D., Gschwend-Steen, K.; Wick, A. E.; Eschenmoser, A. HCA, 1969, 1030–1042.

78% yield, clear colored oil. TLC Rf = 0.50 (20% acetone/80% hexanes); 1H NMR (400 MHz,

CDCl3) δ 7.27 (d, J = 8.8 Hz, 4 H), 6.87 (d, J = 8.8 Hz, 4 H), 4.50 (s, 4 H), 3.78 (s, 6 H); 13C

NMR (100 MHz, CDCl3) δ 159.1, 130.4, 129.3, 113.7, 71.4, 55.2.

1-methoxy-4-(4-nitro-benzyloxymethyl)-benzene 2.65.

85% yield, dark yellow colored oil. TLC Rf = 0.45 (10% acetone/90% hexanes); IR (neat) 3109,

3076, 3003, 2935, 2838, 1561, 1342, 1302, 1246; 1H NMR (400 MHz, CDCl3) δ 8.21 (d, J = 2

Hz, 2 H), 7.51 (d, J = 8.8 Hz, 2 H), 7.26 (d, J = 2 Hz, 2 H), 6.90 (d, J = 8.8 Hz, 2 H), 4.61 (s, 2

H), 4.55 (s, 2 H), 3.81 (s, 3 H); 13 C NMR (100 MHz, CDCl3) δ 159.5, 147.3, 146.1, 129.6,

59

129.5, 129.3, 127.8, 123.6, 114.4, 113.9, 72.5, 70.5, 55.3, 44.9; Anal. Calcd for C15H15NO4: C,

65.92; H, 5.53; N, 5.13. Found: C, 65.80, H, 5.41, N, 5.00.

N-(4-methoxybenzyloxy)phthalimide.

Lit. Ref.: Ramsay, S. L.; Freeman, C.; Grace, P. B.; Redmond, J. W.; MacLeod, J. K.

Carbohydrate Research. 333. 59-71.

58% yield, white colored solid. mp = 134.9-136.3°C (ethyl acetate); TLC Rf = 0.28, 0.57 (20%

ethyl acetate/80% hexanes); 1H NMR (300 MHz, CDCl3) δ 7.82-7.71 (m, 4 H) 7.45 (d, J = 8.4

Hz, 2 H), 6.88 (d, J = 8.4 Hz, 2 H), 5.15 (s, 2 H), 3.80 (s, 3 H); 13C NMR (75 MHz, CDCl3) δ

163.5, 160.4, 134.3, 131.6, 128.8, 125.8, 123.4, 113.9, 79.4, 55.2.

(4-Methoxyphenyl)methyl propargyl ether 2.67.

Lit. Ref.: Marshall, J. A.; Robinson, E. D.; Zapata, A. J. Org. Chem., 1989, 54, 5854–5855

82% yield, Clear oil. TLC Rf = 0.41 (10% Ethyl acetate/90% hexanes); 1H NMR (400 MHz,

CDCl3) δ 7.32 (d, J = 8.4 Hz, 2 H), 6.93 (d, J = 1.8 Hz, 2 H), 4.57 (s, 2 H), 4.17 (d, J = 2.4 Hz, 2

H), 3.82 (s, 3 H), 4.55 (s, 2 H), 2.52 (d, J = 2.4 Hz, 1 H).

1-((4-methoxybenzyl)oxy)-2-nitrobenzene 2.70.

60

76% yield, yellow oil. TLC Rf = 0.30 (10% ethyl acetate/90% hexanes); 1H NMR (400 MHz,

CDCl3) δ 7.83 (dd, J = 1.6, 8.1 Hz, 1H), 7.49 (ddd, J = 1.7, 7.5, 8.4 Hz, 1H), 7.38 (d, J = 8.6 Hz,

2H), 7.14 (dd, J = 1.0, 8.5 Hz, 1H), 7.02 (td, J = 0.9, 7.6 Hz, 1H), 6.91 (d, J = 8.7 Hz, 2H), 5.16

(s, 2H), 3.81 (s, 3H).

(2-((4-methoxybenzyl)oxy)ethyl)trimethylsilane 2.74.

68% yield, red oil. TLC Rf = 0.76 (10% ethyl acetate/90% hexanes); 1H NMR (300 MHz,

CDCl3) δ 7.25 (d, J = 8.4 Hz, 2H), 6.86 (d, J = 8.1 Hz, 1H), 4.40 (s, 2H), 3.78 (s, 3H), 3.54 (td, J

= 0.9, 8.1 Hz, 2H), 0.97 (td, J = 0.9, 8.1 Hz, 2H), 0.00 (s, 9H).

(E)-1-((cinnamyloxy)methyl)-4-methoxybenzene 2.62.

Lit. Ref.: Charette, A. B. Synlett 2002, 176-178.

52% yield, yellow oil. TLC Rf = 0.70 (25% ethyl acetate/75% hexanes); 1H NMR (400 MHz,

CDCl3) δ 7.40 (d, J = 7.2 Hz, 2H), 7.34-7.30 (m, 4H), 7.25 (d, J = 6.3 Hz, 1H), 6.90 (d, J = 8.6

Hz, 2H), 6.63 (d, J = 16.0 Hz, 1H), 6.33 (dt, J = 6.0, 15.9 Hz, 1H), 4.52 (s, 2H), 4.18 (dd, J = 1.4,

6.0 Hz, 2H), 3.82 (s, 3H).

1-methoxy-4-((octadecyloxy)methyl)benzene 2.60.

Lit. Ref.: Kurosu, M. Synthesis 2009, 3633-3641.

61

96 % yield, white solid. mp = 45.6-46.5°C (dichloromethane). TLC Rf = 0.82 (10% ethyl

acetate/90% hexanes); 1H NMR (400 MHz, CDCl3) δ 7.26 (d, J = 8.8 Hz, 2H), 6.87 (d, J = 8.7

Hz, 2H), 4.42 (s, 2H), 3.79 (s, 3H), 3.43 (t, J = 6.7 Hz, 2H), 1.63-1.56 (m, 2H), 1.36-1.25 (m,

34H), 0.88 (t, J = 6.6 Hz, 3H).

ethyl 3-((4-methoxybenzyl)oxy)-3-phenylpropanoate 2.77.

61% yield, clear oil. TLC Rf = 0.47 (10% ethyl acetate/90% hexanes); 1H NMR (300 MHz,

CDCl3) δ 7.39-7.29 (m, 5H), 7.19 (d, J = 8.7 Hz, 2H), 6.85 (d, J = 8.7 Hz, 2H), 4.83 (q, J = 5.1

Hz, 1H), 4.38 (d, J = 11.4 Hz, 1H), 4.23 (d, J = 11.1 Hz, 1H), 4.17-4.06 (m, 2H), 3.80 (s, 3H),

2.85 (dd, J = 9.0, 15.0 Hz, 1H), 2.59 (dd, J = 4.8, 15.3 Hz, 1H), 1.20 (t, J = 7.2 Hz, 3H).

3-[(4-Methoxybenzyl)oxy]propan-1-ol 2.84.

Lit. Ref.: Adje, N.; Breuilles, P.; Uguen, D. Tetrahedron Lett. 1993, 34, 4631-4634.

79% yield, pale yellow oil. TLC Rf = 0.43 (50 % ethyl acetate/50 % hexanes ); 1H NMR (300

MHz, CDCl3) δ 7.28 (d, J = 8.7 Hz, 2 H), 6.91 (d, J = 8.7 Hz, 2 H), 4.48 (s, 2 H), 3.84 (s, 3 H),

3.80 (t, J =5.5 Hz, 2 H), 3.67 (t, J =5.8 Hz, 2 H), 2.17 (bs, 1 H), 1.88 (q, J =5.7 Hz, 2 H).

2-(4-Methoxybenzyloxy)ethanol 2.83.

62

Lit. Ref.: Kukase, K.; Tanaka, H.; Toriib, S.; Kusumoto, S. Tetrahedron Lett. 1990, 31, 389-392.

80% yield, yellow oil. TLC Rf = 0.32 (50 % ethyl acetate/50 % hexanes ); 1H NMR (300 MHz,

CDCl3) δ 7.30 (d, J = 7.8 Hz, 2 H), 6.92 (d, J = 11.6 Hz, 2 H), 4.53 (s, 2 H), 3.84 (s, 3 H), 3.78

(t, J =4.7 Hz, 2 H), 3.61 (t, J =4.8 Hz, 2 H), 1.85 (bs, 1 H).

4-[(4-Methoxyphenyl)methoxy]-2-butyn-1-ol 2.85.

Lit. Ref.: Hatakeyama, S.; Yoshida, M.; Esumi, T.; Iwabuchi, Y.; Irie, H.; Kawamoto, T.;

Yamada, H.; Nishizawa, M. Tetrahedron Lett. 1997, 38, 7887-7890.

36% yield, yellow oil. TLC Rf = 0.52 (50 % ethyl acetate/50 % hexanes ); 1H NMR (300 MHz,

CDCl3) δ 7.30 (d, J = 6.6 Hz, 2 H), 6.91 (d, J = 11.6 Hz, 2 H), 4.56 (s, 2 H), 4.36 (t, J =1.8 Hz, 2

H), 4.21 (t, J =2.1 Hz, 2 H), 3.84 (s, 3 H).

63

Appendix A. 1H AND 13C NMR SPECTRA SUPPLEMENT TO

CHAPTER 2

9 8 7 6 5 4 3 2 1 ppm

1.012

2.222

3.806

5.037

6.870

6.899

7.284

7.312

7.313

9.0

0

1.8

5

2.9

0

1.9

7

1.6

3

1.6

0

O

O

OMe

4-methoxybenzyl 3,3-dimethylbutanoate

64

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

29.768

30.934

48.079

55.333

65.772

114.001

128.455

130.234

159.668

172.326

4-methoxybenzyl 3,3-dimethylbutanoate

O

O

OMe

9 8 7 6 5 4 3 2 1 ppm

3.784

3.872

5.281

6.885

6.914

6.937

6.962

7.376

7.405

7.430

7.433

7.438

7.457

7.463

7.787

7.792

7.813

7.819

3.0

8

3.0

0

2.0

3

3.5

2

2.4

8

0.7

4

O

O

OMeOMe

4-methoxybenzyl 2-methoxybenzoate

65

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm55.323

56.012

66.395

112.096

113.966

114.332

120.097

120.150

128.423

130.046

131.756

133.648

159.371

159.607

166.040

O

O

OMeOMe

4-methoxybenzyl 2-methoxybenzoate

9 8 7 6 5 4 3 2 1 ppm

1.850

1.855

1.873

1.879

3.800

5.104

5.841

5.846

5.893

5.898

6.864

6.874

6.880

6.896

6.903

6.912

6.941

6.964

6.987

6.992

7.010

7.016

7.039

7.062

7.260

7.288

7.297

7.326

7.336

2.8

8

3.0

0

2.0

0

0.6

8

1.7

1

0.6

9

1.6

4

O

O

OMe

(E)-4-methoxybenzyl but-2-enoate

66

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

18.023

55.279

65.835

113.969

122.676

128.364

130.094

145.034

159.647

166.443

(E)-4-methoxybenzyl but-2-enoate

O

O

OMe

9 8 7 6 5 4 3 2 1 ppm

1.656

1.666

1.706

1.747

1.894

1.903

2.002

3.806

5.030

6.869

6.875

6.891

6.898

7.257

7.258

7.279

7.286

6.7

7

9.5

9

3.0

0

2.1

0

1.6

8

1.7

7

O

O

OMe

(3r,5r ,7r )-4-methoxybenzyl adamantane-1-carboxylate

67

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

28.049

36.593

38.903

40.806

55.310

65.656

113.939

128.778

129.593

159.490

177.587

O

O

OMe

(3r,5r ,7r )-4-methoxybenzyl adamantane-1-carboxylate

9 8 7 6 5 4 3 2 1 ppm

3.503

3.506

3.812

5.228

5.267

5.311

5.350

6.853

6.863

6.869

6.885

6.892

6.901

7.260

7.279

7.288

7.294

7.317

7.328

7.342

7.348

7.354

7.362

7.369

7.376

7.389

7.432

7.459

2.7

7

3.0

0

2.0

4

1.7

3

3.9

7

1.6

5

O

O

OMeMeO CF3

(S)-4-methoxybenzyl 3,3,3-trifluoro-2-methoxy-2-phenylpropanoate

68

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

55.314

55.535

67.897

113.992

121.412

125.235

126.746

127.322

128.393

129.586

130.542

132.326

159.966

166.516

(S)-4-methoxybenzyl 3,3,3-trifluoro-2-methoxy-2-phenylpropanoate

O

O

OMeMeO CF3

9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 ppm

3.836

5.093

5.167

6.881

6.904

6.910

7.260

7.282

7.288

7.301

7.308

7.316

7.333

7.344

3.0

0

0.8

5

2.0

3

1.7

6

10.2

9

O

O

OMe

4-methoxybenzyl 2,2-diphenylacetate

69

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

55.403

57.194

66.928

114.028

127.394

127.968

128.723

128.783

130.237

138.809

159.778

172.520

4-methoxybenzyl 2,2-diphenylacetate

O

O

OMe

10 9 8 7 6 5 4 3 2 1 0 ppm

2.124

3.815

5.241

6.880

6.897

6.905

6.927

6.934

7.067

7.070

7.094

7.097

7.252

7.261

7.269

7.272

7.294

7.297

7.319

7.323

7.346

7.368

7.375

7.517

7.522

7.542

7.547

7.568

7.574

8.033

8.039

8.059

8.065

2.7

6

3.0

0

1.9

6

1.7

6

0.7

4

2.6

6

0.8

2

0.7

2

O

O

OMe

O

O

4-methoxybenzyl 2-acetoxybenzoate

70

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

20.827

55.349

66.978

114.099

123.459

123.931

126.118

127.722

130.447

132.089

133.986

150.706

159.894

164.591

169.760

4-methoxybenzyl 2-acetoxybenzoate

O

O

OMe

O

O

9 8 7 6 5 4 3 2 1 ppm

0.829

0.842

0.846

0.856

0.868

0.985

0.997

1.006

1.012

1.021

1.037

1.586

1.601

1.613

1.616

1.628

1.639

1.644

1.655

1.670

3.780

5.051

6.869

6.898

7.281

7.310

1.9

6

1.8

6

0.7

4

3.0

0

2.0

0

1.7

4

1.7

0

O

O

OMe

4-methoxybenzyl cyclopropanecarboxylate

71

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

8.499

12.960

55.211

66.085

113.930

128.296

130.053

159.628

174.744

4-methoxybenzyl cyclopropanecarboxylate

O

O

OMe

9 8 7 6 5 4 3 2 1 ppm

3.828

5.220

5.263

6.849

6.868

6.878

6.885

6.900

6.907

7.134

7.141

7.162

7.169

7.260

7.354

7.372

7.379

7.382

7.411

7.429

7.520

7.548

3.0

0

3.6

5

2.5

7

0.6

9

0.4

0

2.0

2

0.6

4

0.6

6

4-methoxybenzyl 3-((2,4-dichlorobenzyl)oxy)thiophene-2-carboxylate

O

OOMe

S

OCl

Cl

72

9 8 7 6 5 4 3 2 1 ppm

3.783

4.904

6.758

6.787

7.056

7.085

7.392

7.397

7.402

7.415

7.420

7.425

7.430

7.441

7.450

7.466

7.473

7.478

7.489

7.494

7.499

7.505

7.514

7.519

7.528

7.536

7.543

7.554

7.562

7.578

7.584

7.601

3.0

0

2.1

4

1.8

6

1.8

5

13.4

0

0.9

0

O

O

P

MeO

4-methoxybenzyl 2-(diphenylphosphino)benzoate

73

9 8 7 6 5 4 3 2 1 ppm

1.685

1.695

1.728

1.776

1.954

1.964

2.035

6.834

7.249

7.252

7.256

7.260

7.268

7.277

7.283

7.296

7.300

7.305

7.309

7.312

7.330

7.337

7.344

7.355

7.359

0.4

9

7.1

0

7.0

0

3.1

5

0.8

1

10.0

0

(3r ,5r ,7r )-benzhydryl adamantane-1-carboxylate

O

O

2.19

210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 ppm

28.089

36.645

38.933

40.988

76.337

127.050

127.858

128.607

140.841

176.526

O

O

2.19

(3r ,5r ,7r )-benzhydryl adamantane-1-carboxylate

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

ODPM16 8

91

ODPM16 8

92

ODPM11

93

ODPM11

94

ODPM

MeO12

95

ODPM

MeO12

96

ODPM

O2N13

97

ODPM

O2N13

98

ODPM

14

99

ODPM

14

100

ODPM

15

101

ODPM

15

102

ODPM

16

103

ODPM

16

104

ODPM

17

105

ODPM

17

106

ODPM

18

107

ODPM

18

108

ODPM

19

109

ODPM

19

110

DPMO

O

20

111

DPMO

O

20

112

DPMOSiMe321

113

DPMOSiMe321

114

N

O

O

DPMO

22

115

N

O

O

DPMO

22

116

117

118

O OMe

OBnBnO

BnO

DPMO

24

119

O OMe

OBnBnO

BnO

DPMO

24

120

DPMOH

HH

H

H

25

121

DPMOH

HH

H

H

25

122

OEt

DPMO O

26

123

OEt

DPMO O

26

124

OEt

O

DPMO 27

125

OEt

O

DPMO 27

126

NOBn

O

Cbz

H

DPMO28

127

NOBn

O

Cbz

H

DPMO28

128

DPMO OMe29

129

DPMO OMe29

130

DPMO NO230

131

DPMO NO230

132

SMeO2C

DPMO

31

133

SMeO2C

DPMO

31

134

ODPM

32

135

ODPM

32

136

10% 2-Propanol/Hexane

Chiracel OD

NOBn

O

DPMO

Cbz

H

(±)-23

137

10% 2-Propanol/Hexane

Chiracel OD

NOBn

O

DPMO

Cbz

H

(-)-23

138

1% 2-Propanol/Hexane

Chiracel OD

OEt

O

DPMO (±)-27

139

1% 2-Propanol/Hexane

Chiracel OD

OEt

O

DPMO (-)-27

140

References

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146

Chapter 3: Modulation of SHIP for Therapeutic Purposes

Abstract:

The SH2-containing inositol 5’-phosphatase-1 (SHIP1) is an enzyme found in blood cells

that is responsible for the hydrolysis of phosphatidylinositol-3,4,5-trisphosphate to

phosphatidylinositol-4,5-bisphosphate. This enzyme is part of a major cell signaling pathway

(the PI3K pathway) that affects many important cellular functions such as proliferation,

differentiation and adhesion. SHIP1 inhibition has been found to increase blood cell production

and slow the growth of blood cancer cells, and therefore SHIP1 inhibition with small molecules

is being explored. High throughput screening small molecule libraries identified several SHIP1

inhibitors including 3α-aminocholestane (3AC). 3AC and certain other aminosteroids show

selectivity as SHIP1 inhibitors and therefore may have therapeutic applications. Further

synthetic studies have been undertaken to determine which portions of the aminosteroid SHIP1

inhibitor are important for biological activity. In addition, modifications to the molecule which

improve solubility and potency have also been pursued in order to facilitate the evaluation of

these inhibitors in other biological settings. In this chapter the syntheses of a number of

aminosteroid derivatives and the evaluation of these compounds for their potential as SHIP1

inhibitors is described.

PI3K Signaling Pathway

When eukaryotic cells shuttle information about changes in the extracellular environment

to the nucleus the signals must cross the cell membrane. Enzymes on the interior of the cell

membrane are integral to this process, as they initiate signaling cascades inside the cell that

involves a complex system made up of both enzymes and second messengers such as

147

phosphatidylinositols. Phosphatidylinositols play a prominent role in cell signaling. These lipids

are intercalated on the interior of the cell membrane and are used to assist in the transduction of

signals across the plasma membrane from the external environment to the nucleus.

Phosphatidylinositol signaling has a major influence in cell division and survival.1,2 This

signaling also plays a role in cell differentiation and adhesion.1,2

One of the best known phosphatidylinositol signaling pathways is mediated by

phosphatidylinositol-3-kinase, PI3K. PI3K is responsible for phosphorylating

phosphatidylinositol-4,5-bisphosphate, PI(4,5)P2, to form phosphatidylinositol-3,4,5-

trisphosphate, PI(3,4,5)P3 (Figure 3.1). When activated, PI3K can rapidly synthesize PI(3,4,5)P3,

which then activates a number of protein kinases resulting in an accelerating signal cascade

through the cytoplasm to the nucleus. Aberrant activation of PI3K is known to lead to cancer.3,4

The phosphatase and tensin homolog protein, PTEN, also regulates this pathway. The PTEN

protein exerts its influence on the pathway by acting as a 3' inositol phosphatase, reversing the

PI3K reaction by hydrolyzing PI(3,4,5)P3 back to PI(4,5)P2. This function of PTEN is crucial, as

PTEN knockout mice quickly develop terminal cancer.5,6 Other inositol phosphatases hydrolyze

PI(3,4,5)P3 to PI(3,4)P2, a second, but distinct inositol bisphosphate. In blood cells (and other

cells related to the hematopoietic system), SH2-containing inositol 5’-phosphatase or SHIP1, is

the inositol phosphatase that hydrolyzes PI(3,4,5)P3 to PI(3,4)P2.2,7 Unlike PTEN, SHIP1

knockout mice are viable and do not develop terminal cancer, although their immune system is

modified.8,9

148

Figure 3.1: The PI3K Pathway

Many other signaling enzymes are involved in the transmission of the PI3K signal in

order for it to reach the nucleus and exert its effects on cellular metabolism (Figure 3.2). After

PI(3,4,5)P3 is formed from PI3K, it binds with the protein kinase PDK1. PDK1 then

phosphorylates a second protein kinase AKT, which is activated and begins to phosphorylate a

number of other protein kinases.10 Both PI(3,4,5)P3 and PI(3,4)P2 are required in the signaling

pathway in order to fully activate AKT.11,12 Once activated, AKT controls the activation and

inhibition of different functions relating to cellular survival and proliferation. One kinase that

AKT activates is mTOR, which controls regulatory cell growth pathways. Inhibition at the start

of the PI3K signaling pathway would cut off the branching of signals and may restore normal

control of cell growth.

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Figure 3.2: The PI3K Signaling Cascade13

SHIP

SHIP plays a significant role in regulation of the PI3K signaling pathway. By

hydrolyzing PI(3,4,5)P3 to PI(3,4)P2, SHIP modulates the intensity of the signal and influences

immune response and cellular division.14,15,16 There are three major paralogs of the SHIP

enzyme: SHIP1, SHIP2, and sSHIP. The expression of SHIP1 occurs primarily in blood and

bone marrow cells. SHIP2 is expressed in a wide variety of cells throughout the rest of the body.

The sSHIP enzyme is only expressed in stem cells. A genetic study of SHIP1 determined that

the enzyme plays a role in blood cell biology and immunology.14,15,16 Most importantly for this

study, it was found that SHIP1 inhibition induces apoptosis in blood cancer cells.9 This

implicates the development of SHIP1 inhibitors as a possible treatment for hematopoietic

neoplasms.

RTK

PPP

P

PTEN

PI3K

p85

P P

PSHIP P P INPP4 P

AktP

PPDK1/mTORC2

NF-kB BAD FKHR mTORGSK3b

P P P PP

GlucoseMetabolism

CellGrowth

Cell Survival

BtkPLCg

ARFGAPs

ARFGEFs

RhoGEFs

Inflammation AutophagyCell

Migration

PI(4,5)P2 PI(3,4,5)P3 PI(3,4)P2PI(3)P

TAPP Irgm1

Autophagy

150

Attempts at crystallizing the whole SHIP enzyme have not been successful. Potter and

coworkers were able to obtain a crystal structure of a portion of the SHIP2 enzyme containing

the active site (Figure 3.3).17 The crystal structure was obtained when a biphenyl 2,3’,4,5’,6-

pentakisphosphate (BiPh(2,3’,4,5’,6)P5) synthetic ligand was bound to the catalytic site of the

SHIP2 protein. The biphenyl phosphate ligand bonds to the polar residues in the SHIP2 active

site through hydrogen bond interactions in the binding pocket. The 5' phosphate of

BiPh(2,3',4,5',6)P5 mimics the 5'-phosphatase of PI(3,4,5)P3. This phosphate shows hydrogen

bonds to Arg682, Tyr661 and Arg611. The hydrogen-bonding network forces the phosphate into

a conformation where hydrolysis is facilitated. Molecular modeling studies have implicated that

a loop of the enzyme (the PI4M loop) near the active site folds over the (BiPh(2,3’,4,5’,6)P5)

ligand and encloses it after it binds to SHIP2. Analysis of SHIP2 binding to the small molecule

is an excellent starting point for the development of small molecule inhibitors.

Figure 3.3: Crystal Structure of SHIP2

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Rationale for SHIP Antagonist or Agonist

Control of PI(3,4,5)P3 production plays a critical role in signal transduction in the PI3K

pathway. A possible way to govern PIP3 production is manipulation of the phosphatase enzyme

SHIP. Inhibition of the SHIP enzyme would stop PI(3,4,5)P3 from hydrolyzing to PI(3,4)P2

while upregulating SHIP would convert all PI(3,4,5)P3 to PI(3,4)P2. As both PI(3,4,5)P3 and

PI(3,4)P2 are required for full activation of AKT, both inhibition and upregulation of SHIP may

significantly affect the PI3K signaling pathway and could lead to blood cancer cell apoptosis

depending on the molecular pathology of the neoplasm. There are many possible uses for SHIP

inhibitors including cancer, bone marrow transplantation, stem cell mobilization and

transplantation, blood cell production, and obesity.

Cancer

The PI3K-AKT-mTOR pathway is intimately involved in cell survival and therefore has

become a focus for cancer treatment.18,19,20 SHIP1, SHIP2 and PTEN are the enzymes

predominantly responsible for controlling the AKT-mTOR signaling, which influences the

survival of cancer cells and tumors. Since SHIP1 is primarily expressed in hematopoietic cells,

SHIP1 inhibition may be used for therapeutic treatment regarding human blood cell cancers such

as leukemia and multiple myeloma.8

Modulation of the other paralogs of SHIP may also be a useful strategy in the treatment

of other types of cancer. SHIP2 overexpression has been implicated in the development of breast

cancer, for example.7 SHIP2 causes an increase in EGF-induced signaling for various breast

cancers which is atypical. High levels of EGF-induced signaling can lead to an increase of

cellular proliferation for the cancer cells.21 Various breast cancer cells lines overexpress SHIP2

such as MDA-MB-231, SKBR-3, MDA-468, MDA-436, MCF-7 and ZR-75. SHIP2 inhibition

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for the MDA-MB-231 breast cancer cell line showed a dramatic decrease in cell proliferation

demonstrating SHIP2’s potential for therapeutic cancer treatment of breast cancer.

Bone Marrow Transplantation

Small molecule SHIP1 inhibitors could also be effective at minimizing complications for

bone marrow transplant recipients and the management of myelodysplastic syndromes.22,23

SHIP1 inhibitors show potential for therapeutic possibilities in treating Graft vs Host disease

(GvHD) caused by bone marrow transplants.24 Bone marrow transplants play a considerable role

in organ transplants, as well as treatment of cancer and genetic disorders.23 However, these

transplants are risky due to the occurrence of GvHD which can cause rejection of the transplant

and ultimately death. Experiments have shown that transplants of mismatched bone marrow

grafts are well tolerated in SHIP1 knockout mice, as these mice possess a modified immune

system which tolerates the grafts. These mice do well with bone marrow transplants because

they do not develop GvHD due to an increased expression of human T regulatory cell numbers.

Even multiple kinds of mismatched bone marrow grafts are successful in SHIP1 knockout

mice.25 SHIP1 inhibitors therefore have therapeutic potential in the area of organ transplants and

engraftments.

Stem Cell Mobilization and Transplantation

The proliferation of hematopoietic STEM cells (HSCs) is increased in SHIP1 knockout

mice.26 Significantly more HSCs are found in the plasma of SHIP1 knockout mice instead of

typically being found in the bone marrow.8 This suggests the use of a SHIP1 inhibitor could be

used to mobilize STEM cells from the bone marrow to the bloodstream. Once in the

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bloodstream, the HSCs are much easier to harvest so they can then be used in HSC

transplantation.

Blood Cell Production

SHIP1 inhibitors may be effective as a means to boost or protect blood cell production in

cancer patients, helping prevent disease or infection as a result of neutropenia.22,23,26 SHIP1

inhibition in the PI3K signaling pathway leads to an increase of PI(3,4,5)P3 which causes an

increase in cell division specific to blood cells. A small molecule SHIP1 inhibitor could be taken

orally and used in cancer treatment where chemotherapy and radiation kill healthy hematopoietic

cells. Typically protein based growth factors are now used for this purpose, but because of their

peptidic nature these drugs must be given intravenously. In vivo studies with mice indicated an

increase of blood cell production after the mice were administered a SHIP1 inhibitor.8 These in

vivo mice studies demonstrate the therapeutic potential of SHIP1 inhibitors for blood cell

production after chemotherapy or radiation poisoning.27,28

Obesity

SHIP1 inhibition may be used to treat inflammatory pathways that can lead to obesity.

By inhibiting SHIP1, expression of immunoregulatory cells is increased and can promote a lean-

body state. Studies using mice that were fed a high fat diet showed a loss of body weight and fat

content when treated with a SHIP1 inhibitor. Use of a SHIP1 inhibitor in adult aged mice

diminished inflammation in the visceral adipose tissue (VAT) which can cause obesity. These

mice lost body fat and also gained lean muscle mass, despite being on a high calorie diet. Thus

the use of a SHIP1 inhibitor could be a successful treatment for diet-associated obesity.29

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Structure Activity Relationships

High throughput screening with small molecule libraries discovered four types of SHIP

inhibitors8, 35 have been discovered and they fall into the categories of aminosteroids (3.4),

quinoline aminoalcohols (3.5), tryptamines (3.6) and thiophenes (3.7). An example of each can

be seen in Figure 3.4. The aminosteroid 3AC (3.4) demonstrated selectivity for SHIP1 over

other inositol phosphatases unlike 3.5 and 3.6, which are unselective SHIP1/SHIP2 inhibitors,

and thiophenes (like 3.7) which are selective small molecule SHIP2 inhibitors. The parent

compound, 3AC (3.4), was unfortunately found to have very poor water solubility.

Figure 3.4: SHIP Inhibitors

To address the poor water solubility, a number of analogs were synthesized.30

Androsterone derivative 3.9, (Figure 3.5), is more soluble in water and has a higher potency as a

SHIP1 inhibitor. Compound 3.9 is not a selective SHIP1 inhibitor, however, as it shows equal

inhibition of SHIP1 and SHIP2. Acylation or alkylation of the amine significantly reduced

inhibitory activity. Moreover, the inclusion of polar functional groups on the D ring was shown

to decrease activity vs. SHIP1, like in the case of compound 3.13.

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Figure 3.5: Aminosteroid Analogues

From these structure activity studies, a general impression of the binding pocket for the

aminosteroids can be proposed. This model indicates that polar functionality is tolerated on the

A ring while only hydrophobic groups are allowed on ring D (Figure 3.6).8

Figure 3.6: Structure Activity Relationship of the Aminosteroid SHIP inhibitors

The known crystal structure of SHIP2 led to our own molecular modeling of the SHIP1

active site.17 Using the SHIP2 x-ray structure as a guide, a model of the SHIP1 active site was

constructed in silico. Figure 3.7 shows this proposed model of the active site of SHIP1 and a

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model with aminosteroid 3AC docked in the active site. The model for SHIP1 is based on the

crystal structure of the SHIP2 active site, but many of the residues near the active site have been

changed as they are different than those found in SHIP2. The largest changes are seen in the

PI4M loop region (Figure 3.7). In the model of 3.4 binding to SHIP1, the C17 sidechain on the D

ring of the aminosteroid is in the PI4M loop region. In the crystal structure for SHIP2 there is a

threonine in the PI4M loop region, however, in SHIP1 there is a more lipophilic tyrosine. This

difference in amino acids may explain the selectivity of the inhibition for SHIP1 when we have a

sidechain at C17.

Figure 3.7: Proposed model of active site for SHIP1

Figure 3.8 shows the % inhibition of aminosteroid inhibitors 3.4 (3AC), 3.9 (K185), and

3.14 (K118) in the malachite green assay for phosphatase activity. 3AC showed selective

inhibition for SHIP1, where as K185 and K118 showed inhibition for both SHIP1 and SHIP2.

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Figure 3.8: SHIP Inhibition with Aminosteroids

Since androsterone derivative 3.9 (K185) showed improved solubility and an increased

activity as a SHIP1 inhibitor from 3.4 (3AC), aminosteroids without or with a smaller carbon

chain on the D ring were synthesized (Figure 3.9). Based on the molecular modeling studies, it

was thought that an aminosteroid with a smaller carbon chain on the D ring would maintain

selectivity for SHIP1 while maintaining the improved water solubility. The aminosteroid 3.9

was not only synthesized on large scale but the β form of the aminosteroid (K118) was

synthesized as well. In addition, two aminosteroid derivatives with alkenes on the D ring of the

0%

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60%

70%

80%

90%

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steroid were synthesized. Finally, an aminosteroid with a methyl group on the D ring was

prepared.

Figure 3.9: SHIP1 Inhibitors and Potential Analogues

Androsterone derivatives

For the synthesis of analogue 3.9, a supply of steroid 3.19 was needed as the starting

material. Reduction of androsterone 3.18 through a Yamamura-Clemmensen reduction was

explored for this purpose as an alternative to the Wolff-Kishner (Figure 3.10), which was

providing irreproducible yields.31

Figure 3.10: Clemmensen Reduction of Trans-Androsterone

The Clemmensen reduction was thought to be a more attractive methodology because the

reaction is faster and proceeds at a lower temperature than the Wolff-Kishner reduction.31 The

reaction was optimized by varying the amounts of zinc metal and TMSCl used, as well as the

reaction time and concentration. Eventually an 85% yield of the desired product was obtained.

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However, when the reaction scale was increased to two grams, only 56% yield was obtained

(Table 3.1). Also, 1H NMR spectra showed an unidentified minor impurity in the product that

could not be removed. This impurity did not appear in the product when a Wolff-Kishner

reduction was used.

Table 3.1: Clemmensen Reduction of Trans-Androsterone

Entry mmol

Zn/TMSCl

Equivalents

Zn/ TMSCl

Concentration

(M) Time

Percent

yield

1 20/20 100/100 0.01 1 hour 81

2 20/20 100/100 0.01 24 hours 49

3 5/5 25/25 0.01 1 hour 60

4 20/20 100/100 0.04 1 hour 78

5 2/2 10/10 0.1 1 hour 52

6 4/4 20/20 0.1 1 hour 42

7 4/4 20/20 0.04 1 hour 54

8 8/8 40/40 0.04 1 hour 76

9 20/5 100/25 0.04 5 hours 85

10 20/5 100/25 0.04 1 hour 80

11 723/181 100/25 0.04 1 hour 56a

a 2 gram scale (7.23 mmol)

To circumvent the Clemmensen and Wolff-Kishner reactions, hydrazone 3.20 was

prepared (Table 3.2).32 This hydrazone may then be reduced with a number of reducing agents.

Though the proposed synthetic route will introduce more steps to the original synthesis,

producing steroid 3.19 under mild conditions in high yield on large scale was key to our efforts.

Ketone 3.18 was converted to the hydrazone 3.20 by refluxing with hydrazine in ethanol. Crude

hydrazone 3.20 was then exposed to different reduction conditions (Table 3.2), including

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exposure to either potassium tert-butoxide or potassium bis(trimethylsilyl) amide. The reaction

was also performed at room temperature in DMSO or refluxed in toluene. However, none of the

reaction conditions gave a high yield of the product.

Table 3.2: Reduction of Hydrazone 3.20

Entry Base Solvent Temperature Time % Yield

1 KOC(CH3)3 Toluene 110oC 5 hours --

2 KOC(CH3)3 DMSO rt 16 hours --

3 KOC(CH3)3 DMSO rt 8 hours 9 %

4 KOC(CH3)3 DMSO rt 24 hours --

5 KHMDS DMSO rt 22 hours 6%

6 KOC(CH3)3 Toluene 110oC 24 hours 2%

Because of the low yield observed in the preparation of 3.19 through hydrazone removal

of 3.20, the Wolff-Kishner reaction was re-explored. A modified Wolff-Kishner reaction was

employed for the ketone reduction of the androsterone where diethylene glycol was used to

conduct the reaction in a much higher temperature.33 In addition, a brine solution was used in the

workup and methyl tert-butyl ether was used in the extraction in place of HCl and DCM, which

facilitated the isolation of the reaction product.33 The extraction with brine and MTBE was very

clean and contained no precipitates. When DCM and HCl were employed the extraction was

messy and contained insoluble salts making the extraction difficult. The cleaner extraction

conditions with MTBE and brine allowed for a higher yield of product. These conditions

allowed for the large scale reduction of ketone 3.18 with a 69% yield. Later it was found that

water generated by the formation of the hydrazide was lowering the boiling point of the reaction

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mixture in the Wolff-Kishner reaction, which was the cause for the more moderate yields on

large scale. Simply distilling off approximately half the diethylene glycol removed the water and

led to consistently high yields of the desired product.

A large scale synthesis of aminosteroid 3.9 (K185) was needed by our collaborators for

biological testing. Using the modified Wolff-Kishner conditions, androsterone was reduced to

alcohol 3.19. A Mitsunobu reaction was performed on alcohol 3.19 to convert it to phthalimide

3.21. Phthalimide was used for the installation of the nitrogen because of its easy reduction to an

amine. The phthalimide group was then removed with hydrazine to give amine 3.22. HCl (g)

was used to form the aminosteroid salt 3.9 (Figure 3.11).

Figure 3.11: Synthesis of Aminosteroid K185

The aminosteroid K118 (3.14) was synthesized on large scale, as this molecule also

shows significant activity as a SHIP inhibitor and good water solubility properties. Alcohol 3.19

was subjected to a Mitsunobu reaction with iodomethane to provide iodide 3.23. Iodide 3.23 was

displaced with sodium azide to give β azide 3.24. Initially, a lithium aluminum hydride

reduction was used to reduce the azide 3.24 to amine 3.25. However, the aluminum salt

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impurities from the hydride reduction proved difficult to remove. Instead, Staudinger conditions

were used to reduce azide 3.24 to amine 3.25. Amine salt 3.14 was then formed utilizing the

reaction of hydrogen chloride (HCl) gas with amine 3.25 (Figure 3.12).

Figure 3.12: Synthesis of Aminosteroid K118

For the synthesis of aminosteroid K179 (3.15), trans-androsterone was used as the

starting material. The ketone on the D ring first needed to be converted to an internal alkene. In

order to accomplish this transformation, a Shapiro reaction was investigated. Androsterone 3.18

was initially converted to tosylhydrazone 3.26.34 A Shapiro reaction using methyl lithium was

used to transform the tosylhydrazone to alkene 3.27.34 Mitsunobu reaction with DPPA was then

used to introduce the azide in steroid 3.28. Azide 3.28 was reduced to amine 3.29 using lithium

aluminum hydride, and aminosteroid salt 3.15 (K179) was formed using a solution of HCl in

ether and amine 3.29 (Figure 3.13).

163

Figure 3.13: Synthesis of Aminosteroid K179

In addition, the synthesis of aminosteroid 3.16 was performed in a similar manner to the

synthesis of alkene 3.15. A Wittig reaction was performed on trans-androsterone 3.18 which

allowed for the installation of external alkene on the D ring of the steroid. Initially, sodium

hydride was used for the Wittig reaction but no product was observed, perhaps because the

sodium hydride had degraded over time. The use of n-butyl lithium instead of sodium hydride

gave a product yield of 79% for this Wittig reaction. The alcohol 3.30 was then converted to

phthalimide 3.31 through a Mitsunobu reaction. Aminosteroid salt 3.16 was made from alkene

3.32 using HCl in methanol/ethyl acetate (which was conveniently formed by the addition of

acetyl chloride to methanol, followed by the addition of ethyl acetate) to provide the amine salt.

164

Figure 3.14: Synthesis of Alkene 3.16

The synthesis of amine hydrochloride salt 3.17 was then attempted starting with the

reduction of alkene 3.30. The reduction of the alkene on the D ring of 3.30 was performed using

a palladium catalyzed hydrogenation. This reaction allowed for the installation of a methyl

group on the D ring of the steroid nucleus. The stereochemistry of the methyl group is assumed

to be controlled by the nearby axial methyl group, which precludes axial attack and leads

selectively to the product shown. The alcohol 3.33 was then subjected to a Mitsunobu reaction to

provide phthalimide 3.34. Removal of the phthalimide group with hydrazine then gave amine

3.35. Aminosteroid salt 3.17 was formed utilizing HCl (g) and amine 3.35 (Figure 3.15).

165

Figure 3.15: Synthesis of Potential SHIP Inhibitor 3.17

After the proposed SHIP inhibitors were synthesized, they were tested for inhibition of

both SHIP1 and SHIP2 utilizing the malachite green assay.8 The results are shown in Figure

3.16. K185 (3.9) and K118 (3.14) were also included for comparison since they show inhibition

of SHIP1 and SHIP2. However, K185 demonstrated higher toxicity in mice studies than K118.

An exploration of β-isomers may lead to a less toxic SHIP inhibitor. K179 (3.15) was active for

inhibition of both SHIP1 and SHIP2. The biological activity of aminosteroids 3.16 and 3.17 is

still being explored. These studies demonstrate that a longer alkyl C-17 chain on the D ring of

the steroid maybe necessary for selective SHIP1 inhibition. Additionally a C16-C17 alkene is

tolerated in the binding pocket, opening the way for the preparation of other analogs with

substitution at C17 and unsaturation at C16-C17.

166

Figure 3.16: % SHIP Inhibition of Aminosteroids with K179

Conclusions

A number of aminosteroid derivatives were synthesized and tested for their ability to

inhibit SHIP. Removal of the C-17 carbon chain on the D-ring of the steroid was explored. The

steroids 3.9 (K185), 3.14 (K118), and 3.15 (K179) showed high potency but lost selectivity for

SHIP1 inhibition. Molecular modeling predicted a need for a long carbon chain at C-17 for

selective binding to SHIP1 over SHIP2. Aminosteroids with alkenes on the C-17 carbon were

synthesized and showed activity as SHIP inhibitors. Installing alkenes allows for

functionalization of the D ring of the steroid, with the goal being installation of the shortest

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

3AC K185 K118 K179

% In

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167

carbon chain that maintains SHIP1 selectivity but also provides a compound with good water

solubility so it may be used in animal studies. Further studies of the aminosteroid with smaller

carbon chains on the D-ring are now being conducted. These aminosteroids show activity for the

treatment of blood cancer cells and may have uses in the treatment of obesity.

Experimental Procedures

General Information. All anhydrous reactions were run under a positive pressure of argon or

nitrogen. All syringes, needles, and reaction flasks required for anhydrous reactions were dried in

an oven and cooled under an N2 atmosphere or in a desiccator. DCM and THF were dried by

passage through an alumina column. Triethylamine was distilled from CaH2. All other reagents

and solvents were purchased from commercial sources and used without further purification.

Analysis and Purification. Analytical thin layer chromatography (TLC) was performed on

precoated glass backed plates (silica gel 60 F254; 0.25 mm thickness). The TLC plates were

visualized by UV illumination and by staining. Solvents for chromatography are listed as

volume:volume ratios. Flash column chromatography was carried out on silica gel (40-63 μm).

Melting points were recorded using an electrothermal melting point apparatus and are uncorrected.

Elemental analyses were performed on an elemental analyzer with a thermal conductivity detector

and 2 meter GC column maintained at 50 °C.

Identity. Proton (1H NMR) and carbon (13C NMR) nuclear magnetic resonance spectra were

recorded at 300 or 400 MHz and 75 or 100 MHz respectively. The chemical shifts are given in

parts per million (ppm) on the delta (δ) scale. Coupling constants are reported in hertz (Hz). The

spectra were recorded in solutions of deuterated chloroform (CDCl3), with residual chloroform (

7.26 ppm for 1H NMR, δ 77.23 ppm for 13C NMR) or tetramethylsilane ( 0.00 for 1H NMR,

0.00 for 13C NMR) as the internal reference. Data are reported as follows: (s = singlet; d = doublet;

168

t = triplet; q = quartet; p = pentet; sep = septet; dd = doublet of doublets; dt = doublet of triplets;

td = triplet of doublets; tt = triplet of triplets; qd = quartet of doublets; ddd = doublet of doublet of

doublets; br s = broad singlet). Where applicable, the number of protons attached to the

corresponding carbon atom was determined by DEPT 135 NMR. Infrared (IR) spectra were

obtained as thin films on NaCl plates by dissolving the compound in CH2Cl2 followed by

evaporation or as KBr pellets.

5–Androstan–3–ol (3.19)

Lit. Ref.: Norden, S.; Bender, M.; Rullkötter, J.; Christoffers, J. Eur. J. Org. Chem. 2011. 4543–

4550.

In a flame–dried flask, potassium hydroxide (4.764 g, 84.9 mmol) was dissolved in diethylene

glycol (41 mL) by heating. The solution was cooled to rt before adding trans–androsterone (6 g,

20.7 mmol) and hydrazine hydrate (3 mL, 62.1 mmol). The solution was heated to reflux. After 24

h, the solution was cooled to rt and the reaction mixture was quenched by adding brine (600 mL).

The mixture was extracted with MTBE (3 x 200 mL). The organic layers were collected, combined,

dried over magnesium sulfate, filtered, and concd under reduced pressure. Purification was done

with column chromatography (20% ethyl acetate/hexanes) to give 3.19 as a white solid (3.946 g,

69%). 3.19. mp = 149.3–150.7 oC (DCM) (Lit: 151–152 oC); TLC Rf = 0.33 (ethyl acetate:hexane,

1:4); IR (KBr) 3350, 2930, 2845, 1447, 1377, 1133 cm–1; 1H NMR (300 MHz, CDCl3) 3.58

(hept, J = 4.9 Hz, 1H), 1.76–1.82 (m, 1H), 1.70–1.75 (m, 2H), 1.65–1.69 (m, 2H), 1.61–1.63 (m,

169

1H), 1.57–1.60 (m, 1H), 1.52–1.57 (m, 2H), 1.47–1.50 (m, 1H), 1.40–1.45 (m, 1H), 1.33–1.39 (m,

1H), 1.29–1.30 (m, 1H), 1.22–1.28 (m, 4H), 1.04–1.17 (m, 4H), 0.9–1.02 (m, 1H), 0.85–0.93 (m,

2H), 0.80 (s, 3H), 0.68 (s, 3H) 0.60–0.65 (m, 1H); 13C NMR (75 MHz, CDCl3) 71.6, 54.8, 54.7,

45.1, 41.0, 40.6, 39.1, 38.4, 37.3, 36.1, 35.8, 32.7, 31.7, 29.0, 25.7, 21.5, 20.7, 17.7, 12.6.

3–Phthalimido–5–androstane (3.21)

In a 100 mL round bottom flask, 5–androstan–3–ol 3.19 (1.0 g, 3.62 mmol) was dissolved in

dry THF (36 mL). Triphenylphosphine (1.138 g, 4.34 mmol) was added into the solution

followed by diisopropyl azodicarboxylate (DIAD) (0.86 mL, 4.34 mmol). The resulting yellow

solution was stirred continuously at rt for 10 min before adding phthalimide (639 mg, 4.34

mmol). The solution was stirred continuously at rt. After 24 h, the reaction mixture was concd

and the residue was purified with column chromatography (hexanes) to give 3.21 as a white solid

(0.927 g, 63%). 3.21. TLC Rf = 0.39 (10% ethyl acetate/hexane); 1H NMR (300 MHz, CDCl3) δ

7.78-7.83 (m, 2H), 7.67-7.74 (m, 2H), 4.49-4.51 (m, 1H), 0.81-2.12 (m, 33H), 0.73 (s, 3H).

3–amino–5–androstane (3.22)

170

Lit. Ref.: Cowell, D. B.; Davis, A. K.; Mathieson, D. W.; Nicklin, P. D. J. Chem. Soc., Perkin

Trans. 1. 1974, 1505-1513.

In a 250 mL round bottom flask 3–Phthalimido–5–androstane 3.21 (1.413 g, 3.48 mmol) was

suspended in 70 ml MeOH. Hydrazine (13 mL, 271 mmol) was added and the reaction refluxed

for one hour. The solvent was evaporated and the residue was dissolved in DCM (20 mL). The

solution was extracted with NaOH (20 mL, 1M) 5 times. The organic layers were collected,

combined, dried with sodium sulfate, filtered and concentrated. Purification was done with

column chromatography (90:9:1 DCM:MeOH:NH4OH) to give 3.22 as a clear oil (724 mg,

75%). 3.22. IR (KBr) 2926, 2855, 1472, 1378, 1124, 753 cm–1; 1H NMR (300 MHz, CDCl3)

3.18 (bs, 1H), 1.71–1.73 (m, 2H), 1.65–1.69 (m, 3H), 1.61–1.63 (m, 1H), 1.59–1.60 (m, 1H),

1.55–1.57 (m, 2H), 1.50–1.53 (m, 1H), 1.40–1.45 (m, 3H), 1.30–1.32 (m, 1H), 1.23–1.29 (m,

3H), 1.18–1.21 (m, 3H), 1.14–1.18 (m, 2H), 1.07–1.10 (m, 2H), 0.89–1.99 (m, 2H), 0.78 (s, 3H),

0.69 (s, 3H).

3–Amino–5–androstane hydrochloride (3.9)

The –amine 3.22 (1.135 g, 4.12 mmol) was dissolved in diethyl ether (5 mL). Hydrogen chloride

(g), resulting from sulfuric acid being added to sodium chloride, was bubbled into the diethyl ether

which resulted in precipitate formation. The suspension was filtered. The precipitate was collected

and dried under vacuum to afford amine salt 3.9 (1.139 g, 89%) as a white solid. 3.9. mp = 252.2

oC (diethyl ether) (dec.); IR (KBr) 3320, 2945, 1619, 1495, 1443, 1379 cm–1; 1H NMR (300 MHz,

171

CDCl3) 8.45 (bs, 3H), 3.60 (bs, 1H), 1.84 (bs, 2H), 1.62–1.69 (m, 8H), 1.51–1.58 (m, 4H), 1.37–

1.44 (m, 1H), 1.23–1.29 (m, 2H), 1.09–1.20 (m, 4H), 0.92–1.07 (m, 3H), 0.79 (s, 3H), 0.69 (s,

3H); ); 13C NMR (75 MHz, CD3OD) 54.2, 53.3, 48.0, 41.0, 40.6, 38.9, 38.8, 36.3, 36.0, 32.3,

31.6, 28.6, 25.6, 25.0, 20.9, 20.7, 17.8, 11.6. Anal calcd for C19H34ClN: C, 73.16; H, 10.99; N,

4.49. Found: C, 73.56; H, 11.19; N, 4.50.

(3R,5S,8S,9S,10S,13S,14S)–3–iodo–10,13–dimethylhexadecahydro–1H–

cyclopenta[a]phenanthrene (3.23)

In a flame dried round bottom flask, –alcohol 3.19 (1.00 g, 3.62 mmol) and triphenylphosphine

(1.138 g, 4.34 mmol) were dissolved in dry benzene (20 mL). A solution of DIAD (0.86 mL, 4.34

mmol) in dry benzene (8 mL) was added dropwise over several minutes followed by a solution of

iodomethane (0.27 mL, 4.34 mmol) in dry benzene (8 mL). The resulting milky yellow solution

was stirred continuously at rt. After approximately 24 h, the reaction mixture was concd and the

residue was purified through flash column chromatography eluting with hexane which afforded

3.23 (1.194 g, 85%) as a white solid. 3.23. 1H NMR (300 MHz, CDCl3) 4.94 (quint, J = 2.6 Hz,

1H), 1.91 (pt, J = 15.4, 3.3 Hz, 1H), 1.70–1.76 (m, 1H), 1.66–1.69 (m, 2H), 1.59–1.64 (m, 3H),

1.56–1.58 (m, 1H), 1.52–1.54 (m, 1H), 1.49 (t, J = 3.3 Hz, 1H), 1.45 (t, J = 2.2 Hz, 1H), 1.39–1.43

(m, 1H), 1.30–1.36 (m, 1H), 1.28 (d, J = 4.0 Hz, 1H), 1.22–1.26 (m, 2H), 1.18–1.21 (m, 1H), 1.13–

1.17 (m, 2H), 1.07–1.11 (m, 1H), 0.97–1.04 (m, 1H), 0.89–0.95 (m, 1H), 0.83–0.87 (m, 1H), 0.79

(s, 3H), 0.69 (s, 3H).

172

(3S,5S,8S,9S,10S,13S,14S)–3–azido–10,13–dimethylhexadecahydro–1H–

cyclopenta[a]phenanthrene (3.24)

In a flame dried–round bottom flask, iodide 3.23 (1.483 g, 3.84 mmol) and sodium azide (2.496 g,

38.4 mmol) were suspended in dry DMF (20 mL). The suspension was heated to 80 oC. After 5

hours, the solution was cooled at rt before quenching the reaction by adding water (200 mL). The

quenched reaction mixture was extracted with diethyl ether (3 x 200 mL). The organic layers were

collected, combined, dried over magnesium sulfate, filtered, and concd under reduced pressure.

Purification using flash column chromatography with hexane was done to afford azide 3.24 (0.859

g, 74%) as white solid. 3.24. TLC Rf = 0.38 (hexanes); 1H NMR (300 MHz, CDCl3) 3.25 (dt, J

= 12.9, 4.5 Hz, 1H), 1.78–1.86 (m, 1H), 1.72–1.76 (m, 1H), 1.64–1.71 (m, 2H), 1.58–1.63 (m, 2H),

1.52–1.57 (m, 2H), 1.48–1.51 (m, 1H), 1.44–1.47 (m, 1H), 1.40–1.43 (m, 1H), 1.33–1.39 (m, 1H),

1.20–1.31 (m, 4H), 1.02–1.19 (m, 4H), 0.83– 0.99 (m, 3H), 0.80 (s, 3H), 0.68 (s, 3H), 0.61–0.70

(m, 1H).

3β–Amino–5–androstane (3.25)

173

Lit. Ref.: Cowell, D. B.; Davis, A. K.; Mathieson, D. W.; Nicklin, P. D. J. Chem. Soc., Perkin

Trans. 1. 1974, 1505-1513.

In a flame dried flask, azide 3.24 (1.694 g, 5.62 mmol) and triphenylphosphine (2.938 g, 11.2

mmol) was dissolved in dry THF (26 mL). The solution was stirred continuously at rt. After

approximately 2 hours, water (7 mL) was added and the solution was heated to reflux overnight.

The solution was cooled at rt. The organic layer was collected, dried over sodium sulfate, and

concd under reduced pressure. Purification was done with column chromatography (90:9:1 DCM:

MeOH: NH4OH) to give 3.25 as a clear oil (1.456 g, 94%). 3.25. 1H NMR (300 MHz, CDCl3)

2.59-2.74 (m, 1H), 1.99 (bs, 2H), 0.61-1.73 (m, 35H).

3β–Amino–5–androstane hydrochloride (3.14)

Lit. Ref.: Cowell, D. B.; Davis, A. K.; Mathieson, D. W.; Nicklin, P. D. J. Chem. Soc., Perkin

Trans. 1. 1974, 1505-1513.

The β–amine 3.25 (1.456 g, 5.29 mmol) was dissolved in diethyl ether (10 mL). Hydrogen chloride

(g), resulting from sulfuric acid being added to sodium chloride, was bubbled into the diethyl ether

solution which resulted in precipitate formation. The suspension was filtered. The precipitate was

collected and dried under vacuum to afford amine salt 3.14 (1.589 g, 96%) as a white solid. 3.14.

mp = 276.2 oC (diethyl ether) (dec.); IR (KBr) 3449, 2928, 2361, 1984, 1451, 1377 cm–1; 1H NMR

(300 MHz, CDCl3) 8.29 (bs, 3H), 3.13 (bs, 1H), 1.99 (app d, 1H), 1.55–1.580 (m, 10H), 1.38–

1.48 (m, 2H), 1.23–1.35 (m, 4H), 1.06–1.19 (m, 4H), 0.89– 1.02 (m, 3H), 0.84 (s, 3H), 0.68 (s,

3H); 13C NMR (75 MHz, CDCl3) 54.7, 54.5, 51.5, 45.3, 41.0, 40.6, 39.0, 36.9, 35.9, 35.7, 33.3,

174

32.4, 28.5, 27.1, 25.7, 21.3, 20.7, 17.8, 12.5. Anal calcd for C19H34ClN: C, 73.16; H, 10.99; N,

4.49. Found: C, 72.96; H, 10.80; N, 4.31.

(3S,5S,8S,9S,10S,13S,14S)-10,13-Dimethyl-hexadecahydro-1H-cyclopenta[a]phenanthren-

3-ol (3.19).

Lit. Ref.: Xu, S.; Toyama, T.; Nakamura, J.; Arimoto, H. Tetrahedron Letters. 2010, 51, 4534-

4537.

In a round bottom flask, trans-androsterone (58 mg, 0.20 mmol) was dissolved in 3:1

methanol/dichloromethane (5 mL) and cooled to 0oC. Zinc (1.308 g, 20 mmol) was added to the

solution followed by chlorotrimethylsilane (0.635 mL, 5 mmol) dropwise at 0oC. The reaction

was stirred for 1 hour. Solid sodium bicarbonate (2.016 g, 24 mmol) was added to quench the

reaction. The mixture was filtered and the filtrate was concentrated. The residue was diluted

with saturated aqueous ammonium chloride and extracted with dichloromethane. The organic

layer was dried using sodium sulfate, filtered and concentrated. Purification was done with flash

column chromatography (25% ethyl acetate/hexanes) to give solid 3.19 (44 mg, 80%). 3.19. mp

= 149-150oC (CDCl3); TLC Rf = 0.33 (25% ethyl acetate/hexanes); IR (neat) 3349, 2930, 2844

cm-1; 1H NMR (300 MHz, CDCl3) δ 3.59 (m, 1H), 0.59-1.82 (m, 34H).

175

N'-((3S,5S,8R,9S,10S,13S,14S)-3-hydroxy-10,13-dimethyl-tetradecahydro-2H-

cyclopenta[a]phenanthren-17(14H)-ylidene)-4-methylbenzenesulfonohydrazide

Lit. Ref.: Anderson, A.; Boyd, A.C.; Clark, J.K.; Fielding, L.; Gemmell, D.K.; Hamilton, N.M;

Maidment, M.S.; May, V.; McGuire, R.; McPhail, P.; Sansbury, F.H.; Sundaram, H.; Taylor, R.

J. Med. Chem. 2000, 43, 4118-4125.

In a 50 mL round bottom flask, trans-androsterone (2.00 g, 6.89 mmol), p-toluene sulfonyl

hydrazide (1.42 g, 7.62 mmol), and p-toluene sulfonic acid monohydrate (20 mg, 0.1 mmol)

were dissolved in ethanol (10 mL). The reaction refluxed overnight. The next day additional p-

toluene sulfonyl hydrazide (700 mg) and p-toluene sulfonic acid monohydrate (20 mg) were

added. The reaction refluxed for another 5 hours. The solvent was evaporated under reduced

pressure. Purification was done with flash column chromatography (1:1 ethyl acetate/hexanes)

to give KTH-1-123 as white solid (4.006 g, 63%). mp = 161-186oC (1:1 ethyl acetate/hexanes);

TLC Rf = 0.08 (25% ethyl acetate/hexanes); IR (neat) 3400, 3200, 2926, 1597, 1333, 1165 cm-1;

1H NMR (300 MHz, CDCl3) δ 7.82 (d, J = 8.4 Hz, 2H), 7.29 (d, J = 7.8 Hz, 2H), 3.50-3.58 (m,

1H), 2.42 (s, 3H), 0.77-2.22 (m, 28H).

176

(3S,5S,8R,9S,10S,13R,14S)-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-tetradecahydro-

1H-cyclopenta[a]phenanthren-3-ol (3.27)

Lit. Ref.: Anderson, A.; Boyd, A.C.; Clark, J.K.; Fielding, L.; Gemmell, D.K.; Hamilton, N.M;

Maidment, M.S.; May, V.; McGuire, R.; McPhail, P.; Sansbury, F.H.; Sundaram, H.; Taylor, R.

J. Med. Chem. 2000, 43, 4118-4125.

In a flame dried 50 mL round bottom flask, 3.26 was dissolved in dry THF (11 mL) and cooled

to 0oC. Methyl lithium (3 M in diethoxymethane, 2.4 mL, 7.19 mmol) was added dropwise over

5 minutes. A precipitate formed and redissolved as methyl lithium addition continued. The red

solution was stirred at room temperature for 24 hours. Methyl lithium (3 M in diethoxymethane,

1.2 mL, 3.6 mmol) was added to the flask and the reaction stirred for 6 hours. The reaction was

quenched with slow addition of water, then diethyl ether was added. The mixture was acidified

with 2 M hydrochloric acid. The organic layer was separated, washed with water twice then

brine once, dried with sodium sulfate and concentrated. Purification was done using column

chromatography (15% ethyl acetate/hexanes) to give 3.27 as a white solid (248 mg, 41%). 3.27.

mp = 114-118oC (15% ethyl acetate/hexanes); TLC Rf = 0.40 (25% ethyl acetate/hexanes); IR

(neat) 3246, 3044, 2934, 2846, 1449, 1042 cm-1; 1H NMR (300 MHz, CDCl3) δ 5.83 (d, J = 9.3

Hz, 1H), 5.66-5.70 (m, 1H), 3.53-3.64 (m, 1H), 0.75-2.13 (m, 28H).

(3R,5S,8R,9S,10S,13R,14S)-3-azido-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-

tetradecahydro-1H-cyclopenta[a]phenanthrene (3.28)

177

Lit. Ref.: Amiranashvili, L. Sh.; Sladkov, V. I.; Levina, I. I.; Men'shova, N. I.; Suvorov, N.

N. Journal of Organic Chemistry USSR. 1990, 26, # 9.1 p. 1629-1632.

In a 50 mL round bottom flask, alcohol 3.27 (0.24 g, 0.875 mmol) was dissolved in dry THF (9

mL). Triphenylphosphine (0.23 g, 0.875 mmol) was added into the solution followed by

diisopropryl azodicarboxylate (DIAD) (0.17 mL, 0.875 mmol). The resulting yellow solution

was stirred continuously at rt for 10 min before adding diphenylphosphoryl azide (0.23 mL, 1.05

mmol). The solution was stirred continuously at rt. After 24 h, the reaction mixture was concd

and the residue was purified with column chromatography to give 3.28 as a white solid (0.193 g,

74%).%). 3.28. TLC Rf = 0.33 (Hexanes); 1H NMR (300 MHz, CDCl3) δ 5.81-5.83 (m, 1H),

5.69-5.70 (m, 1H), 3.87-3.89 (m, 1H), 0.75- 1.89 (m, 28H).

(3R,5S,8R,9S,10S,13R,14S)-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-

tetradecahydro-1H-cyclopenta[a]phenanthren-3-amine (3.29)

In a flame dried round bottom flask, LAH (0.085 g, 2.13 mmol, 95%) was suspended in dry THF

(2.5 mL). The suspension was cooled at 0 oC using ice/water cold bath before adding the solution

of –azide 3.28 (0.193 g, 0.645 mmol) in dry THF (2.5 mL). The solution was warmed to rt and

then refluxed for 5 hours. The reaction was then cooled to rt before diluting the solution with

THF (5 mL). The diluted reaction mixture was cooled at 0 oC and quenched using a Fieser

method.5 The reaction mixture was stirred continuously until it turned into a milky white

suspension. The suspension was then filtered through celite and washed with THF. The filtrate

was dried over sodium sulfate and concd under reduced pressure. Purification was done with

column chromatography (90:9:1 DCM: MeOH: NH4OH) to afford –amine 3.29 (0.113 g, 64%).

178

3.29. TLC Rf = 0.23 (90:9:1 DCM: MeOH: NH4OH); 1H NMR (300 MHz, CDCl3) δ 5.79-5.82

(m, 1H), 5.67-5.68 (m, 1H), 3.16 (s, 1H), 0.73-1.87 (m, 28H).

(3R,5S,8R,9S,10S,13R,14S)-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-

tetradecahydro-1H-cyclopenta[a]phenanthren-3-amine hydrochloride (3.15)

The –amine 3.29 (0.100 g, 0.366 mmol) was dissolved in diethyl ether (5 mL). A solution of

hydrogen chloride in diethyl ether (0.37 mL, 2 M) was added dropwise which resulted in

precipitate formation. The suspension was filtered and the precipitate was collected, washed with

diethyl ether, and dried under vacuum to afford amine salt 3.15 (0.106 g, 94%) as a white solid.

1H NMR (300 MHz, DMSO-d6) δ 7.98 (bs, 3H), 5.84 (bs, 1H), 5.68 (bs, 1H), 3.34 (bs, 1H), 0.72-

2.03 (m, 34H). Anal calcd for C19H32ClN: C, 73.63; H, 10.41; N, 4.52. Found: C, 73.31; H, 10.15;

N, 4.73.

(3S,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylene-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-ol (3.30)

Lit. Ref.: Norden, S.; Bender, M.; Rullkötter, J.; Christoffers, J. Eur. J. Org. Chem. 2011. 4543–

4550.

179

[Ph3PMe]Br (6.144 g, 17.2 mmol) was suspended in dry THF (24 mL). The suspension was

cooled to 0oC and n-butyl lithium was added slowly (6.88 mL, 17.2 mmol, 2.5 M in hexanes). A

solution of 3.18 (1.0 g, 3.44 mmol) in dry THF (33 mL) was added dropwise, and the resulting

mixture was stirred at reflux for 20 hours. After cooling to room temperature, some water was

added dropwise, and then the mixture was diluted with water (200 mL) and diethyl ether (200

mL). The layers were separated, and the aqueous layer was extracted with diethyl ether (2 X 150

mL). The combined organic layers were dried MgSO4, filtered, and concentrated. Purification

was done with column chromatography (1:1 Et2O: hexanes) to yield 3.30 (0.782 g, 79 as a white

solid. 3.30. TLC Rf = 0.57 (2:1 Et2O:hexanes); 1H NMR (300 MHz, CDCl3) δ 4.61 (s, 1H), 4.59

(s, 1H), 3.49-3.67 (m, 1H), 2.50-2.63 (m, 1H), 2.12-2.31 (m, 1H), 0.65-1.82 (m, 30H).

2-((3R,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylene-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-yl)isoindoline-1,3-dione (3.31)

In a 100 mL round bottom flask, 5–androstan–3–ol 3.30 (0.782 g, 2.71 mmol) was dissolved

in dry THF (27 mL). Triphenylphosphine (0.852 g, 3.25 mmol) was added into the solution

followed by diisopropryl azodicarboxylate (DIAD) (0.64 mL, 3.25 mmol). The resulting yellow

solution was stirred continuously at rt for 10 min before adding phthalimide (478 mg, 3.25

mmol). The solution was stirred continuously at rt. After 24 h, the reaction mixture was concd

and the residue was purified with column chromatography (5% ethyl acetate/hexanes) to give

3.31 as a white solid (0.639 g, 56%). 3.31. TLC Rf = 0.53 (10% ethyl acetate/hexanes); 1H NMR

180

(300 MHz, CDCl3) δ 7.79-7.82 (m, 2H), 7.68-7.71 (m, 2H), 4.62 (s, 1H), 4.61 (s, 1H), 4.49-4.51

(m, 1H), 2.40-2.59 (m, 1H), 0.78-2.31 (m, 32H).

(3R,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylene-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-amine (3.32)

In a 250 mL round bottom flask, steroid 3.31 (0.639 g, 1.53 mmol) was suspended in 77 ml

MeOH. Hydrazine (5.8 mL, 119 mmol) was added and the reaction refluxed for one hour. The

solvent was evaporated and the residue was dissolved in DCM (150 mL). The mixture was

extracted with a NaOH solution (150 mL, 1M) 5 times. The organic layers were collected,

combined, dried with sodium sulfate, filtered and concentrated. Purification was done with

column chromatography (90:9:1 DCM:MeOH:NH4OH) to give 3.32 as a clear oil (384 mg,

87%). 3.32. TLC Rf = 0.09 (90:9:1 DCM:MeOH:NH4OH); 1H NMR (300 MHz, CDCl3) δ 4.61

(s, 1H), 4.59 (s, 1H), 3.22 (bs, 1H), 2.41-2.71 (m, 3H), 2.20-2.26 (m, 1H), 0.73-1.80 (m, 34H).

(3R,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylene-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-amine hydrochloride (3.16)

In a flame dried 50 mL round bottom flask, MeOH (0.11 mL, 2.61 mmol) was suspended in

ethyl acetate (5 mL) and cooled to 0oC. Acetyl chloride (0.19 mL, 2.61 mmol) was added slowly

181

and the reaction stirred for 10 minutes. Amine 3.32 was dissolved in a small amount of ethyl

acetate and added to the flask. A white solution formed. The mixture stirred for 30 minutes. The

product was filtered and dried under vacuum to give 3.16 as a white solid (0.067 g, 40%). 3.16

1H NMR (300 MHz, CD3OD) δ 4.59 (s, 1H), 4.57 (s, 1H), 3.49 (bs, 1H), 2.42-2.59 (m, 1H),

2.10-2.29 (m, 1H), 0.73-2.01 (m, 52H). Anal calcd for C20H34ClN: C, 74.16; H, 10.58; N, 4.32.

Found: C, 74.17; H, 10.47; N, 4.42.

(3S,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethyl-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-ol (3.33)

Lit. Ref.: Norden, S.; Bender, M.; Rullkötter, J.; Christoffers, J. Eur. J. Org. Chem. 2011. 4543–

4550.

In a flame dried 100 mL round bottom flask, steroid 3.30 (0.69 g, 2.4 mmol) was dissolved in

isopropanol (24 mL). Palladium on carbon was added to the flask (0.077g, 0.72 mmol) and the

mixture was put under vacuum. Hydrogen gas was added after the vacuum was removed and the

mixture stirred at 65oC for 17 hours. The mixture was filtered through silica (ether) and

concentrated to give 3.33 as a white solid (0.629 g, 90%). 3.33. TLC Rf = 0.53 (25% ethyl

acetate/hexanes) 1H NMR (300 MHz, CDCl3) δ 3.53-3.62 (m, 1H), 0.72-1.89 (m, 37H), 0.52 (s,

3H).

182

2-((3R,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethyl-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-yl)isoindoline-1,3-dione (3.34)

In a flame dried 100 mL round bottom flask, alcohol 3.33 (0.629 g, 2.17 mmol) was dissolved in

dry THF (22 mL). Triphenylphosphine (0.682 g, 2.6 mmol) was added into the solution followed

by diisopropryl azodicarboxylate (DIAD) (0.52 mL, 2.6 mmol). The resulting yellow solution

was stirred continuously at rt for 10 min before adding phthalimide (0.383 g, 2.6 mmol). The

solution was stirred continuously at rt. After 24 h, the reaction mixture was concd and the residue

was purified with column chromatography (hexanes) to give 3.34 as a white solid (0.445 g,

49%). 3.34 1H NMR (300 MHz, CDCl3) δ 7.79-7.82 (m, 2H), 7.68-7.70 (m, 2H), 4.47-4.52 (m,

1H), 0.73-2.1 (m, 36H), 0.54 (s, 3H).

(3R,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethyl-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-amine (3.35)

In a 50 mL round bottom flask, steroid 3.34 (0.445 g, 1.06 mmol) was suspended in 11 ml

MeOH. Hydrazine (4 mL, 82.7 mmol) was added and the reaction refluxed for one hour. The

solvent was evaporated and the residue was dissolved in DCM (20 mL). The mixture was

extracted with a NaOH solution (20 mL, 1M) 5 times. The organic layers were collected,

183

combined, dried with sodium sulfate, filtered and concentrated. Purification was done with

column chromatography (90:9:1 DCM:MeOH:NH4OH) to give 3.35 as a clear oil (215 mg,

70%). 3.35 1H NMR (300 MHz, CDCl3) δ 3.18 (bs, 1H), 0.71-1.75 (m, 38H), 0.53 (s, 3H).

(3R,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethyl-hexadecahydro-1H-

cyclopenta[a]phenanthren-3-amine hydrochloride (3.17)

Amine 3.35 (0.215 g, 0.743 mmol) was dissolved in diethyl ether (10 mL). Hydrogen chloride

(g), resulting from sulfuric acid being added to calcium chloride, was bubbled into the diethyl

ether solution which resulted in precipitate formation. The suspension was filtered. The

precipitate was collected and dried under vacuum to afford amine salt 3.17 (0.184 g, 76%) as a

white solid. 3.17 1H NMR (300 MHz, CDCl3) δ 8.45 (bs, 3H), 3.60 (bs, 1H) 0.73-1.82 (m, 35H),

0.53 (s, 3H). Anal calcd for C20H36ClN: C, 73.69; H, 11.13; N, 4.30. Found: C, 73.73; H, 10.81;

N, 4.26.

184

Appendix B. 1H AND 13C NMR SPECTRA SUPPLEMENT TO

CHAPTER 3

9 8 7 6 5 4 3 2 1 ppm

0.685

0.805

0.806

0.890

0.931

1.085

1.099

1.107

1.110

1.114

1.129

1.135

1.143

1.171

1.221

1.225

1.234

1.239

1.249

1.261

1.265

1.269

1.272

1.292

1.302

1.306

1.343

1.376

1.402

1.409

1.421

1.449

1.459

1.528

1.536

1.547

1.558

1.561

1.569

1.577

1.591

1.596

1.602

1.618

1.627

1.663

1.668

1.682

1.694

1.707

1.718

1.727

1.738

3.587

43.0

4

1.0

0

H

H

H H

HO

3.19

(3S,5S,8S,9S,10S,13S,14S)-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-ol

185

9 8 7 6 5 4 3 2 1 ppm

0.698

0.851

0.882

0.898

0.922

0.937

0.952

0.961

0.977

1.105

1.111

1.124

1.142

1.155

1.167

1.220

1.227

1.236

1.262

1.275

1.292

1.334

1.376

1.402

1.556

1.567

1.582

1.595

1.600

1.608

1.616

1.625

1.643

1.652

1.665

1.671

1.677

1.683

1.698

1.709

1.716

1.729

1.834

1.858

1.867

4.501

7.678

7.688

7.696

7.697

7.706

7.795

7.804

7.813

7.823

3.0

0

28.7

1

0.8

6

1.7

8

1.5

4

NH

H H

H

O

O 3.21

2-((3R,5S,8S,9S,10S,13S,14S)-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-yl)isoindoline-1,3-dione

186

9 8 7 6 5 4 3 2 1 ppm

1.180

1.190

1.200

1.212

1.225

1.252

1.261

1.298

1.362

1.388

1.395

1.434

1.442

1.475

1.493

1.502

1.514

1.546

1.556

1.587

1.608

1.615

1.639

1.655

1.667

1.695

1.705

1.715

2.401

3.212

40.0

5

2.4

4

1.0

0

H

H

H H

H2N 3.22

(3R,5S,8S,9S,10S,13S,14S)-10,13-dimethylhexadecahydro-1H -cyclopenta[a]phenanthren-3-amine

9 8 7 6 5 4 3 2 1 ppm

0.991

1.015

1.027

1.070

1.094

1.129

1.158

1.195

1.228

1.283

1.368

1.391

1.433

1.548

1.578

1.603

1.618

1.628

1.652

1.691

1.831

3.607

8.446

32.9

0

1.0

0

2.3

8

H

H

H H

H3NCl 3.9

(3R,5S,8S,9S,10S,13S,14S)-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-aminium chloride

187

9 8 7 6 5 4 3 2 1 ppm

0.691

0.799

0.860

0.914

0.950

0.991

1.088

1.132

1.142

1.150

1.155

1.164

1.169

1.181

1.191

1.200

1.227

1.241

1.253

1.263

1.281

1.294

1.318

1.413

1.420

1.432

1.443

1.452

1.460

1.482

1.494

1.505

1.529

1.539

1.549

1.569

1.574

1.579

1.583

1.596

1.605

1.612

1.622

1.631

1.636

1.642

1.669

1.674

1.681

1.686

1.698

1.709

1.724

1.737

4.949

37.5

4

0.8

1

1.0

0

H

H H

H

I3.23

(3R,5S,8S,9S,10S,13S,14S)-3-iodo-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthrene

9 8 7 6 5 4 3 2 1 ppm

0.686

0.805

0.899

0.934

0.990

1.089

1.104

1.109

1.113

1.131

1.142

1.148

1.155

1.173

1.236

1.249

1.262

1.275

1.281

1.286

1.297

1.303

1.315

1.338

1.378

1.407

1.419

1.448

1.453

1.489

1.495

1.507

1.532

1.540

1.545

1.548

1.553

1.564

1.574

1.595

1.601

1.606

1.620

1.631

1.675

1.688

1.698

1.717

1.729

1.738

1.750

1.794

1.800

3.258

46.2

0

1.0

0

H

H H

H

N3 3.24

(3S,5S,8S,9S,10S,13S,14S)-3-azido-10,13-dimethylhexadecahydro-1H -cyclopenta[a]phenanthrene

188

9 8 7 6 5 4 3 2 1 ppm

0.657

0.662

0.683

0.785

0.873

0.890

0.909

0.914

0.930

0.973

1.084

1.097

1.105

1.127

1.132

1.162

1.169

1.202

1.207

1.214

1.222

1.237

1.253

1.266

1.276

1.294

1.307

1.400

1.407

1.419

1.431

1.439

1.446

1.496

1.505

1.556

1.564

1.567

1.589

1.595

1.600

1.617

1.625

1.647

1.657

1.666

1.679

1.687

1.700

1.711

1.716

1.720

1.729

1.988

4.0

3

3.0

0

23.7

4

2.2

4

0.8

8

H

H

H H

H2N 3.25

(3S,5S,8S,9S,10S,13S,14S)-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-amine

9 8 7 6 5 4 3 2 1 ppm

1.144

1.170

1.185

1.200

1.208

1.231

1.260

1.271

1.298

1.342

1.380

1.405

1.446

1.478

1.506

1.525

1.545

1.572

1.587

1.603

1.626

1.656

1.672

1.681

1.723

1.758

1.793

1.806

1.976

2.021

3.126

8.304

4.8

4

31.5

0

1.0

5

1.0

0

2.5

7

H

H

H H

H3NCl 3.14

(3S,5S,8S,9S,10S,13S,14S)-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-aminium chloride

189

9 8 7 6 5 4 3 2 1 ppm

0.768

0.806

0.919

0.961

0.975

1.005

1.020

1.062

1.082

1.184

1.196

1.234

1.258

1.282

1.298

1.310

1.324

1.340

1.355

1.367

1.383

1.415

1.426

1.465

1.580

1.662

1.675

1.688

1.701

1.716

1.731

1.761

1.786

1.806

1.828

1.886

1.927

2.009

2.045

2.069

2.189

2.216

2.423

2.454

3.579

4.108

4.132

7.260

7.276

7.303

7.786

7.806

7.812

7.833

0.9

6

3.0

0

26.4

0

1.0

2

3.5

2

0.8

3

0.3

1

0.6

6

1.7

0

0.3

2

1.9

1

HO

H

H

H H

NNHTos

3.26

N'-((3S,5S,8R,9S,10S,13S,14S)-3-hydroxy-10,13-dimethyldodecahydro-1H-cyclopenta[a]phenanthren-17(2H,10H,14H)-ylidene)-4-methylbenzenesulfonohydrazide

9 8 7 6 5 4 3 2 1 ppm

0.726

0.746

0.760

0.837

0.969

0.981

1.013

1.234

1.248

1.263

1.275

1.296

1.305

1.311

1.323

1.335

1.343

1.353

1.373

1.385

1.387

1.411

1.418

1.424

1.468

1.511

1.525

1.535

1.543

1.551

1.559

1.566

1.574

1.583

1.591

1.597

1.658

1.669

1.678

1.690

1.703

1.712

1.730

1.740

1.881

1.886

1.889

3.588

5.684

5.689

5.694

5.699

5.815

5.820

5.823

42.5

9

1.2

2

1.0

0

1.0

0

HO

H

H

H H

3.27

(3S,5S,8R,9S,10S,13R,14S)-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ol

190

9 8 7 6 5 4 3 2 1 0 ppm

0.825

0.843

0.859

1.061

1.190

1.201

1.212

1.235

1.254

1.268

1.284

1.300

1.324

1.337

1.350

1.359

1.379

1.388

1.402

1.422

1.430

1.439

1.453

1.466

1.477

1.488

1.498

1.510

1.520

1.529

1.549

1.561

1.566

1.584

1.669

1.681

1.695

1.706

1.716

1.726

1.735

1.743

1.880

1.885

1.887

3.874

3.884

3.892

5.691

5.696

5.701

5.818

5.821

5.826

5.829

3.0

0

23.2

2

0.9

9

0.9

2

0.8

3

0.7

1

0.7

0

H

H H

H

N3

3.28

(3R,5S,8R,9S,10S,13R,14S)-3-azido-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-tetradecahydro-1H-cyclopenta[a]phenanthrene

9 8 7 6 5 4 3 2 1 ppm

0.683

0.747

0.779

0.813

1.055

1.192

1.200

1.214

1.224

1.243

1.256

1.267

1.279

1.296

1.317

1.334

1.349

1.409

1.418

1.429

1.461

1.468

1.476

1.492

1.499

1.506

1.526

1.553

1.565

1.578

1.590

1.602

1.679

1.692

1.704

1.709

1.721

1.729

1.742

1.833

1.841

1.866

1.878

1.884

1.891

1.916

1.921

1.929

3.213

5.689

5.694

5.699

5.820

5.825

47.1

9

1.3

8

1.0

1

1.0

0

H2NH

H H

H

3.29

(3R,5S,8R,9S,10S,13R,14S)-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-tetradecahydro-1H-cyclopenta[a]phenanthren-3-amine

191

10 9 8 7 6 5 4 3 2 1 0 ppm

1.144

1.187

1.233

1.269

1.314

1.339

1.374

1.389

1.412

1.460

1.471

1.542

1.565

1.611

1.652

1.756

1.817

1.845

1.897

2.012

2.019

2.033

2.041

2.060

2.071

2.082

2.091

3.605

5.639

5.644

5.658

5.663

5.784

5.789

5.803

5.808

8.432

29.2

1

0.7

9

1.0

0

0.7

5

0.7

5

2.7

0

H3NH

H H

H

Cl

3.15

(3R,5S,8R,9S,10S,13R,14S)-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-tetradecahydro-1H-

cyclopenta[a]phenanthren-3-aminium chloride

9 8 7 6 5 4 3 2 1 ppm

0.768

0.825

0.944

0.959

0.979

0.987

1.001

1.017

1.037

1.147

1.176

1.188

1.218

1.233

1.255

1.259

1.269

1.275

1.289

1.310

1.341

1.351

1.361

1.377

1.391

1.416

1.429

1.519

1.544

1.552

1.561

1.570

1.577

1.587

1.598

1.611

1.632

1.644

1.669

1.696

1.708

1.718

1.738

1.750

1.764

1.778

1.788

1.807

1.818

1.827

3.592

4.605

4.613

4.620

33.6

7

0.9

6

0.8

8

0.8

2

2.0

0

HOH

H H

H

3.30

(3S,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylenehexadecahydro-1H-cyclopenta[a]phenanthren-3-ol

192

9 8 7 6 5 4 3 2 1 ppm

0.778

0.867

0.891

0.950

0.975

0.988

1.019

1.026

1.170

1.199

1.211

1.240

1.250

1.280

1.289

1.321

1.333

1.361

1.380

1.394

1.419

1.573

1.592

1.605

1.619

1.642

1.657

1.673

1.684

1.710

1.722

1.735

1.783

1.794

1.822

1.834

1.861

1.870

1.910

2.035

2.242

4.491

4.501

4.509

4.611

4.619

7.676

7.687

7.695

7.705

7.792

7.802

7.810

7.821

32.0

2

0.9

1

0.9

3

2.0

0

1.8

1

1.5

6

NH

H H

H

O

O3.31

2-((3R,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylenehexadecahydro-1H-cyclopenta[a]phenanthren-3-yl)isoindoline-1,3-dione

10 9 8 7 6 5 4 3 2 1 0 ppm

0.514

0.731

0.753

0.771

0.784

0.806

0.815

0.946

0.966

0.985

1.002

1.008

1.023

1.044

1.139

1.167

1.182

1.194

1.208

1.216

1.239

1.252

1.266

1.294

1.308

1.331

1.345

1.367

1.380

1.406

1.419

1.450

1.482

1.501

1.556

1.592

1.602

1.615

1.634

1.649

1.658

1.667

1.679

1.690

1.721

1.732

1.749

1.761

1.789

1.800

2.231

2.445

4.593

4.601

4.606

33.8

7

1.0

2

3.0

7

0.9

1

2.0

0

H2NH

H H

H

3.32

(3R,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylenehexadecahydro-1H-cyclopenta[a]phenanthren-3-amine

193

9 8 7 6 5 4 3 2 1 ppm

0.556

0.732

0.774

0.808

0.831

0.851

0.866

0.877

0.999

1.014

1.020

1.035

1.183

1.196

1.214

1.226

1.238

1.248

1.257

1.267

1.277

1.289

1.301

1.311

1.317

1.325

1.331

1.346

1.374

1.392

1.403

1.410

1.445

1.455

1.536

1.587

1.592

1.621

1.632

1.652

1.664

1.674

1.686

1.702

1.714

1.747

1.759

1.783

1.794

1.804

3.489

4.578

4.585

4.592

52.0

9

1.0

3

0.6

5

1.5

2

2.0

0

0.3

4

H3NH

H H

H

Cl 3.16

(3R,5S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-methylenehexadecahydro-1H-cyclopenta[a]phenanthren-3-aminium chloride

10 9 8 7 6 5 4 3 2 1 0 ppm

0.530

0.722

0.792

0.806

0.813

0.829

0.904

0.916

0.920

0.929

0.945

0.956

0.968

0.979

1.054

1.071

1.093

1.109

1.118

1.132

1.148

1.157

1.185

1.194

1.199

1.208

1.227

1.232

1.238

1.251

1.262

1.269

1.283

1.293

1.304

1.324

1.345

1.375

1.500

1.519

1.537

1.544

1.554

1.568

1.632

1.644

1.655

1.673

1.686

1.697

1.709

1.740

1.752

1.775

3.589

3.0

0

36.9

2

0.2

1

0.8

6

HOH

H H

H

3.33

(3S,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethylhexadecahydro-1H -cyclopenta[a]phenanthren-3-ol

194

10 9 8 7 6 5 4 3 2 1 0 ppm

0.541

0.733

0.809

0.831

0.855

0.910

0.934

0.943

0.970

0.982

1.002

1.102

1.125

1.154

1.185

1.195

1.219

1.232

1.250

1.263

1.293

1.306

1.330

1.346

1.355

1.378

1.420

1.441

1.554

1.570

1.582

1.596

1.601

1.609

1.621

1.630

1.639

1.650

1.663

1.672

1.679

1.702

1.715

1.822

1.861

1.870

7.677

7.687

7.694

7.696

7.705

7.793

7.803

7.811

7.822

3.2

0

35.6

1

1.0

0

1.9

7

1.6

8

NH

H H

H

O

O3.34

2-((3R,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-yl)isoindoline-1,3-dione

9 8 7 6 5 4 3 2 1 ppm

0.524

0.717

0.766

0.781

0.790

0.802

0.825

0.913

0.926

0.953

0.965

0.988

1.123

1.150

1.159

1.172

1.182

1.192

1.203

1.218

1.234

1.247

1.291

1.327

1.344

1.376

1.399

1.411

1.419

1.430

1.437

1.445

1.452

1.466

1.481

1.489

1.516

1.525

1.539

1.547

1.560

1.569

1.582

1.594

1.599

1.604

1.627

1.639

1.651

1.669

1.681

1.692

1.734

1.748

3.3

4

37.7

0

1.0

0

H2NH

H H

H

3.35

(3R,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-amine

195

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9 8 7 6 5 4 3 2 1 ppm

1.009

1.021

1.074

1.089

1.116

1.147

1.184

1.208

1.231

1.290

1.313

1.344

1.365

1.509

1.560

1.576

1.627

1.646

1.724

1.736

1.753

1.765

1.809

1.822

3.598

8.447

3.0

0

34.8

3

0.0

3

0.9

7

2.6

4

H3NH

H H

H

Cl

3.17

(3R,5S,8S,9S,10S,13R,14S,17S)-10,13,17-trimethylhexadecahydro-1H-cyclopenta[a]phenanthren-3-aminium chloride

196

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15. Tu, Z.; Ninos, J. M.; Ma, Z.; Wang, J.-W.; Lemos, M. P.; Desponts, C.; Ghansah, T.;

Howson, J. M.; Kerr, W. G. Blood. 2001, 98, 2028-2038.

16. Desponts, C.; Hazen, A. L.; Paraiso, K. H. T.; Kerr, W. G. Blood. 2006, 107, 4338-4345.

17. Mills, S. J., C. Persson, G. Cozier, M. P. Thomas, L. Tresaugues, C. Erneux, A. M. Riley,

P. Nordlund, and B. V. L. Potter. ACS Chem. Biol. 2012, 7, 822-828.

18. Alkan, S.; Izban, K. F. Blood. 2002, 99, 2278–2279.

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19. Harvey, R. D.; Lonial, S. Future Oncol. 2007, 3, 639–647.

20. Bunney, T. D.; Katan, M. Nat. Rev. Cancer. 2010, 10, 342–352.

21. Prasad, N. K.; Tandon, M.; Badve, S.; Snyder, P. W.; Nakshatri, H. Carcinogenesis.

2008, 29, 25–34.

22. Collazo, M. M.; Wood, D.; Paraiso, K. H. T.; Lund, E.; Engelman, R. W.; Le, C.-T.;

Stauch, D.; Kotsch, K.; Kerr, W. G. Blood. 2009, 113, 2934-2944.

23. Ghansah, T.; Paraiso, K. H. T.; Highfill, S.; Desponts, C.; May, S.; McIntosh, J. K.;

Wang, J.-W.; Ninos, J.; Brayer, J.; Cheng, F.; Sotomayor, E.; Kerr, W. G. J. Immunol.

2004, 173, 7324-7330.

24. Wang, J.–W.; Howson, J. M.; Ghansah, T.; Desponts, C.; Ninos, J. M.; May, S. L.;

Nguyen, K. H. T.; Toyama–Sorimachi, N.; Kerr, W. G. Science. 2002, 295, 2094-2097.

25. Wahle, J. A.; Paraiso, K. H. T.; Costello, A. L.; Goll, E. L.; Sentman, C. L.; Kerr, W. G.

J. Immunol. 2006, 176, 7165–7169.

26. Rauh, M. J.; Ho, V.; Pereira, C.; Sham, A.; Sly, L. M.; Lam, V.; Huxham, L.;

Minchinton, A. I.; Mui, A.; Krystal, G. Immunity. 2005, 23, 361-374.

27. Xiao, M.; Whitnall, M. H. Curr. Mol. Pharmacol. 2009, 2, 122–133.

28. Donnelly, E. H.; Nemhauser, J. B.; Smith, J. M.; Kazzi, Z. N.; Farfán, E. B.; Chang, A.

S.; Naeem, S. F. South. Med. J. 2010, 103, 541–544.

29. Srivastava, N.; Iyer, S.; Sudan, R.; Youngs, C.; Engelman, R. W.; Howard, K. T.; Russo,

C. M.; Chisholm, J. D.; Kerr, W. G. JCI Insight, Accepted.

30. Viernes, Dennis. Unpublished results.

31. Xu, S.; Toyama, T.; Nakamura, J.; Arimoto, H. Tetrahedron Lett. 2010, 51, 4534-4537.

32. Suginome, H.; Uchida, T. Tetrahedron Lett. 1973, 25, 2289-2292.

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Maidment, M.S.; May, V.; McGuire, R.; McPhail, P.; Sansbury, F.H.; Sundaram, H.;

Taylor, R. J. Med. Chem. 2000, 43, 4118-4125.

35. Fuhler, G. M.; Brooks, R.; Toms, B.; Iyer, S.; Gengo, E. A.; Park, M. Y.; Gumbleton, M.;

Viernes, D. R.; Chisholm, J. D.; Kerr, W. G. Mol. Med. 2012, 18, 65..

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Kyle Timothy Howard

Department of Chemistry kthoward@syr.edu 1-014 Center for Science and Technology 717-318-8885 Syracuse, NY 13244-4100

Education

Ph.D. Chemistry, Advisor: Prof. John D. Chisholm, Syracuse University. Anticipated August 2016.

M.Phil. Chemistry, Advisor: Prof John D. Chisholm, Syracuse University. May 2012.

B.S. Chemistry (major) and Mathematics (minor), York College of Pennsylvania. May 2010.

Honors

William D. Johnson Award for Outstanding Graduate Teaching (2015)

Publications

1. Howard, K. T.; Duffy, B. C.; Linaburg, M. R.; Chisholm, J. D. “Formation of DPM ethers using O-diphenylmethyl trichloroacetimidate under thermal conditions.” Org. Biomol. Chem., 2016, 14, 1623-1628. DOI: 10.1039/C5OB02455B.

2. Howard, K. T.; Chisholm, J. D. “Preparation and Applications of 4-Methoxybenzyl Esters in Organic Synthesis.” Org. Prep. Proced. Int., 2016, 48:1, 1-36. DOI: 10.1080/00304948.2016.1127096. [Invited Review, Peer Reviewed]

3. Srivastava, N.; Iyer, S.; Sudan, R.; Youngs, C.; Engelman, R. W.; Howard, K. T.; Russo, C. M.; Chisholm, J. D.; Kerr, W. G. “SHIPi promotes an immunoregulatory milieu in adipose tissue to reverse age- and diet- associated obesity and metabolic syndrome.” JCI Insight, Accepted.

4. Fernandes, S.; Brooks, R.; Park, M-Y.; Srivastava, N.; Russo, C.M.; Howard, K.T.; Chisholm, J.D.; Kerr W.G. “SHIP Inhibition Enhances Murine Autologous and Allogeneic Hematolymphoid Cell Transplantation.” EBioMedicine, 2015, 2, 205-213. DOI:10.1016/j.ebiom.2015.02.004

5. Duffy, B.C.; Howard, K. T.; Chisholm, J. D. “Alkylation of Thiols using Trichloroacetimidates under Neutral Conditions.” Tetrahedron Lett. 2015, 56, 3301-3305. DOI:10.1016/j.tetlet.2014.12.042

6. Shah, J.P.; Russo, C.M.; Howard, K. T.; Chisholm, J. D. “Spontaneous Formation of PMB Esters Using 4-Methoxybenzyl-2,2,2-trichloroacetimidate.” Tetrahedron Lett. 2014, 55,1740-1742. DOI:10.1016/j.tetlet.2014.01.097

7. Adhikari, A.A.; Shah, J.P.; Howard, K. T.; Russo, C. M.; Wallach, D. R.; Linaburg, M. R.; Chisholm, J. D. “Convenient Formation of DPM Esters Using

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Diphenylmethyl Trichloroacetimidate.” Synlett. 2014, 283-287. DOI: 10.1055/s-0033-1340293

8. Howard, K. T.; Duffy, B. C.; Mahajani, N.; Russo, C. M.; Wallach, D. R.; Wu, Y.; Chisholm, J. D. “Formation of PMB Ethers Under Thermal Conditions with 4-Methoxybenzyl-2,2,2-trichloroacetimidate.” In preparation.

Presentations

1. Howard, K. T.; Chisholm, J. D. “Convenient formation of PMB and DPM ethers with trichloroacetimidates under thermal conditions.” Presented at the 248th American Chemical Society National Meeting & Exposition, San Francisco, CA, August 10-14, 2014, ORGN-983. Poster presentation.

2. Howard, K. T.; Chisholm, J. D. “Convenient Formation of PMB and DPM Ethers with Trichloroacetimidates under Thermal Conditions.” Presented at the 31st Annual Graduate Student Symposium at the University at Buffalo, Buffalo, NY, May 19-21, 2014. Abstract P19. Poster presentation.

3. Howard, K. T.; Viernes, D. R.; Kerr, W. G.; Chisholm, J. D. Synthetic Studies on SHIP1 Inhibitors. Presented at the 38th Northeast Regional Meeting of the American Chemical Society, Rochester, NY, Sept. 30-Oct. 3, 2012, NERM-28. Poster presentation.

4. Howard, K. T.; Kaminsky, L.; Beck, J. J.; Halligan, K. M. Synthesis of a tricyclic natural product as a means to combat the navel orangeworm. Presented at the 239th American Chemical Society National Meeting & Exposition, San Francisco, CA, March 21-25, 2010, CHED-1142. Poster presentation.

Research Experience

Research Areas: Organic synthesis and medicinal chemistry, synthesis and structure activity relationship studies of SHIP inhibitors, formation of PMB and DPM ethers using trichloroacetimidates using thermal conditions. Lab Techniques: Characterization of novel organic compounds utilizing Nuclear Magnetic Resonance (NMR) Spectroscopy (1H, 13C), Infrared (IR) Spectroscopy, High Resolution Mass Spectroscopy (HRMS), Polarimetry, combustion analysis, Liquid Chromatography–Mass Spectrometry (LC–MS) and high pressure liquid chromatography, thin layer chromatography. Undergraduate Mentoring: Syracuse University undergraduate students and summer Research Experience for Undergraduates (REU) participants.

Teaching Experience

Graduate Teaching Assistant for Organic Chemistry I & II Recitations • Guest lectured for Organic Chemistry lecture when Professor was unavailable.

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• Designed worksheets, practice exams, and their corresponding answer keys for students. • Facilitated discussion relevant to organic chemistry topics discussed in the lecture. • Assisted in proctoring and grading exams. • Held weekly office hours for students to provide extra help.

Graduate Teaching Assistant for Organic Chemistry I & II Laboratory

• Conducts lectures relevant to the experiments to be performed. • Develop students’ knowledge in chemistry including laboratory techniques essential in handling glassware, reagents, and equipment.

References

1. Professor John D. Chisholm, Department of Chemistry, Syracuse University.

E-mail: jdchisho@syr.edu; Phone: (315) 443–6894.

2. Professor James Kallmerten, Department of Chemistry, Syracuse University.

E-mail: jkallmer@syr.edu; (315) 443-2854.

3. Professor Kathleen Halligan, Department of Chemistry, York College of

Pennsylvania. E-mail: khalliga@ycp.edu; (717) 815-6872.