Download Fianal Exam

Chem 224A
March 12th
Fianal Exam
Your Name _______________
1. How would you prepare:
a) 15 points
b) 15 points
2. a) (20 points) Provide a mechanism for the following transformation:
3. a) (15 points) Suggest how would 1H NMR look like for the following compound. Please label each group of protons
that you would expect to give a signal, give a range (1 to 2 ppm) of the expected chemical shifts, the multiplicity of these
signals, and the value of the integrals. (For example: Ha, 3-4 ppm, doublet, 3H).
b) (5 points) How many carbon NMR resonances do you expect for this compound?
4. (20 points) In a particular gene that carries information for the sequence of protein A, a single change in a base pair
occurred AT pair was switched into GC pair. This base pair was found in a part of the gene that is transcribed. Despite
the change in the identity of the base pair, the protein A1 that was made from the mutated gene was functionally
indistinguishable from the original protein A (let’s say it catalyzed the same reaction in a same way with the same
selectivity and at the same rate).
Propose 3 explanations for the fact that proteins A and A1 are functionally indistinguishable even though they come
from two genes with different sequences. Briefly (2 sentences maximum) explain each one.
5. (10 points) ATCG sequence is complementary to what sequence.
6. a) (15 points) IR carbonyl stretches of amides are of lower energy than the IR carbonyl stretches of esters. Why? Use
drawings of chemical structures to explain.
b) (5 points) Based on the difference in energy of carbonyl stretches for esters and amides, suggest which class of
compounds is more electrophilic at the carbonyl carbon. Explain in no more than 2 sentences.
7. (15 points) Draw the structure of Val Glu Pro tripeptide.
8. (20 points) Please provide the products of the following reactions.
9. (20 points) How would you transform A into B (more than one step needed)