15 1. Given below is the structure of Griseofulvin. Griseofulvin is an orally administered

antifungal drug. It is used both in animals and humans, to treat fungal infections of the skin and nail fungus. It was discovered in the culture broth of certain species of the mold Penicillium in 1939.

o

Griseofulvin

a. Please fil l in the table below relating to Griseofulvin. (2) Molecular formula Cn l^\nC l ^^io q

I (1) 1 value (index of unsaturation, hydrogen deficiency) 7 (8) Number of ( i f the answer is 0, please fi l l that in) _^

: pi bonds ^ pi orbitals _sp^ carbons . sp- carbons IO sp carbons

10 2. Given below is an example of a group of compounds called hydroxamic acids. When

these compounds are treated with strong acid, there are three sites that can become 0 protonated i.e. react as bases with acid..

:0 :

a.

2.?

'U

H

f

a hydroxamic acid y /

Draw the structure of the three possible monoprotonated (conjugate acids) species.

A

10 3. a.

One of the species is more favorable than the other two. Draw that structure and explain why using a resonance structure. Show the arrow to go from one resonance form to the other.

N

0 ^ \

d

' 1

can deioca^^'^'^

Indicate i f the following reactions will proceed as written (yes or no. pKa table ^ (ocl | f o r a_ r e a r , I ^ 1 /odi

-the lor^f, (xc-.ci . f taseuj^"^ fyc.usd hCXUG (d f^'iQhei

attached). What is the pKa of compounds A and B?

N a N H -

H I C Na+

fN/H3

NaOH //-GO )

id.l J

Na+ H:0

B

b. Looking at the structures of the conjugate bases, explain why one is much more stable than the other (drawings are a good way to answer this).

7 dL

can cje^'ocU/^C, ccpxrgt, cannal 10 4. Given below is the structure of 1, 2-ethanediol.

H

a. Draw Newman projections of thg^ 3 low energy conformations of 1, 2-ethanediol, sighting down the C-C bond. Label each as anti. eclipsed or gauche etc. Use the projections given, just fi l l in the appropriate atoms

old

^2 gaochc^

b. Circle the most stable conformation, based on what you know about conformations.

c. It turns out that the for the alcohol 1, 2-ethanediol, the gauche conformation is the most stable.. What are possible reasons why the gauche conformation is the most stable? Be

^ very, very brief.

16 5. Fill in the following table pertaining to the number of different types of protons and

carbons in each compound..

chiral

plcxm

Compound

a. o

b. (CHjjjCH c.

d. H- -CH,

0 '

e. Be very careful uhd

" 14

no. of different protons

2

no. of different carbons

3

Provide an acceptable lUPAC name for compounds b and e. [ ^ b. . , / ^ Ch^

Are any of the compounds above chiral? Which ones? (Graded right-1/2 wrong)

/ c

I

9 6

11 7.

a. Draw the most stable conformation for the two compounds below. Be very careful, drawings that make no sense will be marked wrong.

2>

b. Circle the planar structure above that represents the most stable compound of the two.

Write one structure for each of the following molecular formulas and descriptions. First, figure out the I value. (Ipt) Make sure all valences are satisfied and there are no formal charges. Indicate the hybridization at each carbon for P A R T B O N L Y . I f you do not follow instructions you will get no credit for the hybridization, a. Cf\f>

an alcohol with no carbon-carbon multiple bonds

ei(h '

b. C ,H , ,N a primary amine with no^rings

s 7 s f I 5 n 3 2.

i - r . I

8. The following data shows that the cyano group (CN) increases the acidity of the hydroxyl group on phenol.

NC

- O H - O H

phenol

P^ a 10.0

3-cyanophenol

{ a. Circle the most acidic compound above.

b. Explain what "effects'' are in are occurring to exhibit the values above. This should be done very briefly with structures and key words. ^

^ ^ . c y ^ n o ,r\ducPj^ oni^X-^ ^\j^n

5-

sf re sor\

p) 44 ^1 c

9. Given below are 'H and '^ C spectra for two compounds of molecular fcMfiula C g H m O . f^ Each compound has a strong peak in the IR around 1716 cm '. C . ^ Compound A

H Q2 signcJ^ 6

H irfJrt

/3r

\ I ' I ' \ \ \^\'I'\'Ir 200 180 160 140 120 100 80 60 40 20 0

ppm Compound B

/3 C

5'

I 1 1 1 1 1 \ 1 y 1 1 ^ y \ p 200 180 160 140 120 100 80 60 40 20 0 . ^

a. Provide structures for Compounds A and B (make sure you mark each one). jf\C d^

3L /^P^^/7

^ ^ p 6

I C-Ppe-f b State two reasons why you made the choices you did.

c.

h

Why does the 'H-NMR for Compound A only integrate for 2 protons and 3 protons when there are a total of 10 protons?