CHEM 109, EXAM 1 SP20

1________

1. FUNdamentals (a) (5 poin ) Provide the pKa of each of the follo ing compounds on the lines provided.

(b) (10 poin ) Each molecule belo has t o or more functional groups. Circle and name all functional groups.

(c) (5 poin ) Functional Groups Dra simple e amples of molecules containing the functional groups belo (4 molec le , 1 f nc ional g o p pe molec le). Each molecule must have at least 3 carbons. No abbreviations such as R groups or squiggl lines. Aldehyde Ketone Ester Thiol

(d) (20 poin ) Happ bela ed 4-20! Tetrahydrocannabinolic acid (THCA) is one of man cannabinoids produced b marijuana plants. There are man different protons in THCA. Determine the t o most acidic protons and list their approximate pKa’s in the bo provided (pKa1 is the most acidic proton). Dra the two conjugate bases in the space provided. No abbreviations allo ed and no mechanism (arro s) required.

Ipt I2pkaeach units ok0 16 50 10 5

alkeneoa.ioIylateagkohdg uioester

O o.O carabao'dalcohol amine

TEH CHEE SH

o

503 10302pKaunits ok

CHEM 109, EXAM 1 SP20

2________

2. Mechanism Warm-up

(a) (15 poin ) Follo the arro s and draw the products.

(b) (10 poin ) Add arrows to complete the mechanism. Do no add mo e in e media e . Add an acids (H+) and bases (:B) needed to complete each step as ritten.

(c) (15 poin ) Add the missing elements in the h dration reaction belo draw the missing intermediate in the bo provided, then add the missing arrows in each of the follo ing steps. Add as man acids (H+) and bases (:B) needed to complete each step as ritten.

9ptsz breakC H T ImissingZbforgank to chargeform N

coNHzH

00kiq oA6ptsOH 2 form C H

Zbreak OF2 form O H

922

Z

B HozIpt arrowIpt sarron

Ipt base Iptacid

a

g5Pts

CHEM 109, EXAM 1 SP20

3________

3. Mechanisms with Cannabis

(a) (5 poin ) Indicate all bonds broken & formed in the electrophilic aromatic substitution reaction of olivetolic acid ith GPP to make CBGA, the metabolic intermediate that can be made into an cannabinoid. List the atoms connected in each bond (e . C-H broken) and clearl indicate the atom(s) on the structures. No mechanism here that s part (b)!

(b) (15 poin ) Add arrows in both steps to e plain each transformation.

(c) (20 poin ) Arrow story indicate all bonds broken & formed (e . C-H broken) as a product of each indicated arro in the decarbo lation of the cannabinoid belo . Dra the full structure of the product.

Hac HI IfC O z 2

3 2gBs22

3 Ng 23 fromhere isok too

B It formed 1OH broken 2 57 9 ItGOT formed2 TT YC broken 2C H formed 2 Is

OH

4 C Cbroken4 C Hformed2 rest of structure

CHEM 109, EXAM 1 SP20

4________

4. Reaction Mechanisms Bring in acids (H+) and bases (:B) here necessar . You ma define abbreviations (R groups) to simplif structures, but be sure to draw the bonds needed to draw the complete mechanism. There are several correct a s of dra ing each mechanism. A minim m of one eac ion in e media e i eq i ed fo each. Sho ho e e bond i b oken & fo med! (a) (20 poin ) The reaction bet een PMP and pyruvate is a ke step in the bios nthesis of alanine. Dra the arrow-pushing mechanism and intermediate(s) involved in this transformation.

(b) (20 poin ) Dra the arrow-pushing mechanism and intermediate(s) involved in this h drol sis reaction.

MR B formedIt H ENo HT

IFF eshmoretest.L.pe Ero

O BOTHokar TOHypts Pinkard fpurthpeer gmix ofthetwo COP intrnd

writerHo H B

ToR

B Hquartet

41 offBOTH0k ory

mix ofthetwoHt R5pts intendlongestmech 2 1

92 z NH

IT II its'iEo risingB

2 2 II 2 pts per intermediate

CHEM 109, EXAM 1 SP20

5________

5. Amino Acids & Polyprotic Acids (a) (15 poin ) Dra the dominant ionic species of the arginine at the indicated pH ranges based on the given pKa s (pKa1 2.0; pKa2 9.0; pKaR 12.5). Indicate all charged atoms ith circled formal charges.

(b) (25 poin ) The molecule belo is used to treat schi ophrenia and bipolar disorder. The form belo is under acidic conditions (pH < 5). Its three pKa s are given ne t to its corresponding proton. Draw the three conjugate bases of this drug, indicating the pH range and net charge of each structure in the spaces provided.

N

N

ON

ON

F

H

H

H pKa3 8.0

pKa2 6.0

pKa1 5.0

pH < 5

net charge ________

:B

____ < pH < ____

net charge ______

:B

____ < pH < ____

net charge ______

:B

____ < pH < ____

net charge ______

p9 12.5 2 10.7550 0.5 ok

pI pH where solin has highestto concentration of no net chargecpd0

Hannett Hannah Huynh Arg11 11 1 11 INHz Lp NHz Te NH LpHzN zH HzN C0 HzN 9

2 I O I mortpetuffYffong20

Heto

Efi'I FoI

35 62

fg ofI8 X 6 8

O I