Synthesis of p38α MAP kinase inhibitors

By: Vita Koren (100481835)

Introduction – The MAP kinase Pathway

Enzymes that catalyze the transfer of a phosphate from ATP to the needed molecule

Involved in growth, proliferation, differentiation and apoptosis of cells

Cancer invasion = loss of control of the above functions

2Dhillon, A., Hgan, S., Rath, O. and Kolch, W. (2007). MAP kinase signalling pathways in cancer. Oncogene. 26: 3279-3290

The p38α Component of MAP kinase

p38α------------------

3Roux, P and Blenis, J. (2004). ERK and p38 MAPK-Activated Protein Kinases: a Family of Protein Kinases with Diverse Biological Functions. Microbiol Mol Biol Rev. 68(2): 320-344

Activated during the secondary phosphorylation Important role in regulation of cytokine

production in response to stressTNF-αIL-1β

Promotes diseases Rheumatoid ArthritisType 1 DiabetesCancer

Previously Discovered Inhibitors

Several inhibitors have been found

p38α is sensitive to these inhibitors at submicromolar IC50 values

4Alessi, D., Cuenda, A., Cohen, P., Dudley, D. and Saltiel, A. (1995). PD 098059 Is a Specific Inhibitor of the Activation of Mitogen-Activated Protein Kinase Kinase in Vitro and in Vivo. Biol Chem, 270: 27488-27494

Potency of Experimental Molecule Goal: Develop and optimize stable methodology for the

preparation of an initial scaffold which can be applied towards drug development of modified new p38α MAP kinase inhibitor

5Baur, B., Storch, K., Martz, K., Goettert, M., Richters, A., Rauh, D. and Laufer, S. (2013). Metabolically Stable Dibenzo[b,e]oxepin-11(6H)‑ones as Highly Selective p38 MAP Kinase Inhibitors: Optimizing Anti-Cytokine Activity in Human Whole Blood. MedChem. 8561-8578

O

O

dibenzo[b,e]oxepin-11(6H)-one

O

O

3-phenylbenzo[c]oxepin-5(1H)-one

vs.

Proposed Synthesis

6

OH

OH

OH

O-PG O-PG

O-PG

OH

O-PG

O

OH

O

O

O

H

O

Protection of Alcohol

Reaction TBDMSCl (equiv.)

Et3N (equiv.) Yield (%)

1 (air) 1.0 4.0 432 (argon) 1.0 4.0 0

3 (air) 0.9 4.5 55

OH

OH

OH

O

TBDMSClTriethylamine

CH2Cl2

Si

7Green, T. and Wuts, P. (1999). Protective Groups in Organic Synthesis. Wiley-Interscience, New York, 127-141, 708-711

Reaction TBDMSCl (equiv.)

Et3N (equiv.) Yield (%)

1 (air) 1.0 4.0 432 (argon) 1.0 4.0 0

3 (air) 0.9 4.5 55

Procedure

8

OH

OH

OH

O

TBDMSClTriethylamine

CH2Cl2

Si

1H NMR SpectraOH

OSi

9

Oxidation of the AlcoholH

OSolventSi

Oxidizing agentOH

OSi

O

101. Corey, E. and Suggs, J. (1975). Pyridinium chlorochromate is a readily available, stable reagent, that oxidizes a wide variety of alcohols to carbonyl compounds with high efficiency. Tetrahedron Lett. 16: 2647-2650 2. Rowlands, G. (2002). Oxidation and Reduction. Sussex. Retrieved from: http://www.massey.ac.nz/~gjrowlan/oxid/alco.pdf3. Bolm, C., Magnus, A. and Hildebrand, J. (2000). Catalytic Synthesis of Aldehydes and Ketones under Mild Conditions Using TEMPO/Oxone. Organic Lett. 2(8): 1173-1175

Reaction Reagents (equiv.)

Solvent Temperature

Time Yield (%)

1 Ca(ClO)2 (0.67) MeCNAcetic acid

H2O

0ºC 1 hr 20

2 MnO2 (1.1) Hexane -10 ºC 3 hrs 03 PCC (1.5) DCM r.t 2 hrs 60

 1H NMR SpectraH

OSi

O

11

Introduction of Phenylacetylene

Reagents

SolventOSi

OH

OSi

H

O

Reaction

Reagents (equiv.) Solvent

Temperature

Time Yield (%)

1 Phenylacetylene (5.0)

n-butyllithium (5.0)

THF -78ºCrt 2 hrs 0

2 Phenylacetylene (1.3)

Zinc iodide (2.5)Triethylamine (2.5)

Toluene 80ºC 30 mins

44

121.Taylor, C and Bolshan, Y. (2014). Metal- free synthesis of ynones from acyl chlorides and potassium alkynyltrifluoroborate salts. OrgLett. 16(2): 488-4912.Yuan, J., Wang, J., Zhang, G., Liu, C., Qi, X., Lan, Y., Miller, J., Kropf, A., Bunel, E. and Lei, A. (2015). Bimetallic zinc complex – active species in coupling of terminal alkynes with aldehydes via nucleophilic addition/ Oppenauer oxidation. Chem Commun. 51: 576-579

 1H NMR Spectra OH

OSi

13

Proposed Mechanism

14

H

OZnI

R

OH

R

H+

ZnI2

HI

ZnI

H

O

R

More Oxidations

Reagents

Solvent

O

OSi

OH

OSi

Reaction

Reagents (equiv.)

Solvent

Temperature

Time

Yield (%)

1 PCC (1.5) 

DCM r.t 2 hrs  65

15Corey, E. and Suggs, J. (1975). Pyridinium chlorochromate is a readily available, stable reagent, that oxidizes a wide variety of alcohols to carbonyl compounds with high efficiency. Tetrahedron Lett. 16: 2647-2650

13C NMR Spectra 

O

OSi

16

Removal of the Protecting Group

Reagents

Solvent

O

OH

O

OSi

17Fuestro, S., Sancho, A., Acena, J. and Sanz-Cervera, J. (2009). Flurous TBAF: A convenient and selective reagent for fluoride-mediate deprotections. J. Org Chem. 74: 6398-6401

Reaction

Reagents (equiv.)

Solvent Temperature

Time Yield (%)

1 Cs2CO3 (1.0) DMF/H2O

100ºC 1 hr 0

2 TBAF (1.5) DMF r.t 1 hr 03 TBAF (2.5) DMF r.t 3 hrs 04 HF (1.9) DMF r.t 1 hr 05 TBAF (1.1) DMF -10ºC 1 hr 06 HF-pyridine DMF r.t 40

mins0

Conclusion Significant progress for the synthesis of initial

scaffold for an inhibitor of p38α MAP kinase has been made

Protection, oxidation and propargylic alcohol addition was accomplished

The compound has never been synthesized and needs to be optimized

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O

OSi

OH

OH

4 Steps

250 mg 23 mg9%

Future Direction

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O

O

3-phenylbenzo[c]oxepin-5(1H)-oneOH

O

O

O

Si

OH

OHO

O

H

Si

X

O

OX

2 Steps 4 Steps

Acknowledgements A huge thank you to my supportive and

insightful supervisor Dr. Bolshan for all his help inside and outside the laboratory

Thank you to Kayla for always answering my questions and providing great advice

Pleasure working alongside all of my lab companions: Ifedi, Stefan, Dylan and William

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