Organic Chemistry III

Professor Carl C. Wamser

Chem 336 - Spring 2007

Exam 2 Answer Key

1. (15 points) Write accurate names for the following:

a)

sodium p-nitrophenoxide

b)

o-isobutylbenzenediazonium chloride

c)

m-methoxyphenyltrimethylammonium hydroxide

m-methoxy-N,N,N-trimethylanilinium hydroxide

d)

(R)-5-(ethylamino)octanoic acid

e)

beta-D-ribopyranose

2. (15 points) Write accurate structures for the following:

a) N-methyl-N-nitrosoaniline

b) 2,5-dicyano-1,4-benzoquinone

c) N-benzyl-1-octadecanamine

d) an L-ketopentose

e) beta-D-fructofuranose

3. (15 points) Arrange the following in order with respect to the property indicated. Write MOST and LEAST under the compounds with the highest and lowest values, respectively.

a) basicity

MIDDLE / / LEAST / / MOST

b) basicity

MOST / / LEAST / / MIDDLE

c) ease of hydrolysis in acid

LEAST / / MIDDLE / / MOST

d) reactivity in nucleophilic substitution

MIDDLE / / LEAST / / MOST

e) equivalents of HIO4 needed for complete reaction

MIDDLE / / MOST / / LEAST

4. (15 points) Write a complete mechanism for the acid-catalyzed hydrolysis of the compound shown below. Bring the sugar to its open-chain form. Show all steps and all resonance forms for any intermediates involved.

Hydrolysis could also occur in the opposite order, i.e., opening of the ring first, then hydrolysis of the methyl hemiacetal.

5. (10 points) Show a sequence of reactions that could be used to prepare p-bromobenzonitrile.

Show how the reaction sequence would differ if the target compound were m-bromobenzonitrile.

To create meta, simply reverse the order of the first two steps.

(or create benzonitrile first, then brominate)

6. (10 points) Complete the following synthetic sequence by adding the missing reagents at each step.

7. (20 points) A quinone may be converted to a hydroquinone by a nucleophilic addition reaction, as illustrated below. (Hint - think Michael addition)

Write two complete mechanisms - using base catalysis or using acid catalysis.
Show all steps and all resonance forms for any intermediates involved.

Base catalysis:

Acid catalysis: