Chemistry 332 - Winter 1997

Exam 2: Chapters 11, 12, 14

1. (15 points) Write a complete name for each of the following compounds, including designation of stereochemistry if it is specifically shown. Use any naming system as long as it gives an unambiguous result.

a) (3 pts)

b) (3 pts)

c) (5 pts)

d) (4 pts)


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

a) (3 pts) protonated cyclohexanone (both resonance forms)

 

b) (3 pts) deprotonated cyclohexanone (both resonance forms)

 

c) (5 pts) beta-D-glucose linked from position 1 to C-5 of beta-D-ribose

 

d) (4 pts) 3,4-diphenylpyrrole

 


3. (15 points) Complete each of the following reactions by adding the structure of the missing part: either the starting compound, the necessary reagents and conditions, or the final products. Indicate stereochemistry if it is specific.

a)

b)

 

c)

d)

 

e)


4. (12 points) Complete the missing parts of the following synthetic sequence:


5. (12 points) Write a structure for D-idose in a pyranose ring with beta stereochemistry at its anomeric carbon. Include both a Haworth projection and a chair form.

 


6. (15 points) Write a complete mechanism for the base-catalyzed Claisen condensation of ethyl cyclopentanecarboxylate using sodium ethoxide. Show all steps and show resonance forms for any intermediates.

 


7. (16 points) Lysine is an amino acid that contains two amine groups with different pKa values. The structure is shown in its fully protonated form below, with its three pKa values. Referring to the pH diagram below, write the structures of the major forms that would be expected in solution within each of the pH ranges marked A, B, C, and D.

 

Explain why the two amine groups have pKa values that differ by so much, when they each could be categorized as primary alkyl amines.