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Chemistry 14D
Winter 2010
Final Exam Part A
Page 1
OK to “Ph” anywhere where appropriate on part A and part B of this exam.
The formation and hydrolysis of amides is of fundamental importance to the biological synthesis and degradation of
proteins. The kinetics and mechanism of amide hydrolysis have been studied extensively. For example, hydrolysis
of molecule A in pure water is very slow.
O
H2O
Hydrolysis very slow
N
CH3
CH3
Molecule A
In questions 1–11 we explore some aspects of amide chemistry and related topics.
1.
(2) In the boxes write the two major product of the hydrolysis of molecule A in the presence of aqueous NaOH.
O
NaOH
H2 O
N
CH3
and
CH3
2.
(3) Complete this statement by adding no more than ten words: Hydrolysis of molecule A with aqueous NaOH
is faster than hydrolysis with water by itself because...
3.
(6) Write the mechanism for the reaction of question 1.
4.
(2) In the boxes write the two major products of the hydrolysis of molecule A in the presence of aqueous
H2SO4.
O
H2SO4
H2 O
N
CH3
and
CH3
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Chemistry 14D
Winter 2010
Final Exam Part A
Page 2
5.
(3) Complete this statement in twenty words or less: Hydrolysis of molecule A with aqueous H2SO4 is faster
than hydrolysis with water by itself because...
6.
(10) Write the mechanism for the reaction of question 4.
7.
(6) Enzymes may also be used for amide hydrolysis. Describe two different ways in which an enzyme causes
amide hydrolysis to be faster than hydrolysis with water by itself. Be very specific.
Reason #1 (twenty words or less):
Reason #2 (twenty words or less):
8.
(2) Chymotrypsin is a serine protease that uses the side chain of serine to perform the amide hydrolysis. The
side chain of serine is CH2OH. Consider the rate of the same amide hydrolysis using a cysteine protease. (The
side chain of cysteine in CH2SH.) Based on the information given what can we conclude about the rate of these
two reactions (circle one)?
(a) Rate of reaction with serine protease > rate of reaction with cysteine protease
(b) Rate of reaction with serine protease < rate of reaction with cysteine protease
(c) Cannot determine
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Chemistry 14D
9.
Winter 2010
Final Exam Part A
Page 3
(4) Compared to the same reaction of molecule A, the rate of hydrolysis
with NaOH for molecule B is (circle one):
Faster
O
Slower
Complete this explanation by adding no more than twenty words: This is
because...
N
NO2
CH3
Molecule B
10. (4) Compared to the same reaction of molecule A, the rate of hydrolysis
with NaOH for molecule C is (circle one):
Faster
O
Slower
O
CH3
Complete this explanation by adding no more than twenty words: This is
because...
11. (4) Compared to the same reaction of molecule A, the rate of hydrolysis
with NaOH for molecule D is (circle one):
Faster
CH3
Molecule C
NO2
O
Slower
Complete this explanation by adding no more than twenty words: This is
because...
CH3
Molecule D
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Chemistry 14D
Winter 2010
Final Exam Part A
Page 4
12. (10) Write the mechanism for this transesterification reaction.
O
O
H2SO4
CH3CH2OH
OCH3
OCH2CH3
13. (11) Write the mechanism for this imine hydrolysis reaction.
CH3
N
O
HCl
+ CH3NH3
H2O
H
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Chemistry 14D
Winter 2010
Final Exam Part A
Page 5
14. (2) What reactants must be mixed to make H2C=CHMgBr? Complete the following a reaction, but do not
include the mechanism.
H2C
CHMgBr
Questions 15–17 refer to the equilibrium between ascorbic acid (molecule E) and its isomer (molecule F).
OH
OH
O
O
O
O
OH
OH
HO
OH
Molecule E
HO
O
Molecule F
15. (1) For the equilibrium between molecule E and molecule F (circle one): Keq < 1
Keq > 1
16. (6) Complete these two specific and distinctly different reasons for your choice in the previous question by
writing E or F in each blank as needed, and then by adding no more than twenty words in each case.
Molecule ____ is more stable than molecule ___ because...
Molecule ____ is more stable than molecule ___ because...
17. (4) Write a mechanism for the conversion of molecule E into molecule F via aqueous H2SO4.
18. (2) Draw an enamine that has exactly 7 carbons atoms and exactly 13 hydrogen atoms, plus any number of
atoms of other elements as necessary. Your enamine cannot be aromatic.
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Chemistry 14D
Winter 2010
Final Exam Part A
Page 6
19. (6) Write the major organic product(s) in the boxes. Assume reagents above/below the arrows are in excess
unless otherwise specified. Do not include any mechanism details. If no reaction occurs write “NR.”
O
O
O
NaBH4
(a)
(CH3)2N
OCH3
O
O
(b)
CH3CH2OH
MgBr
1.
(CH3)2N
OCH3
2. H3O
20. (12) Write a mechanism.
CH3
O
CO2
1. CH3CH2CO2CH3, CH3O,
CH3OH
2. NaOH
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Chemistry 14D
Winter 2010
Final Exam Part A
Page 7
Question 21 is an extra credit questions on pharmaceutical chemistry. The points earned from this question will be
added to your total score for part A of this exam, but cannot raise the score above 100.
21. (6) After each term in write one choice from the choices list that is the best match. The choices may be used
once, or more than once, or not at all.
(a) DNA cutter:
(b) DNA intercalator:
(c) DNA alkylator:
(d) Suicide inhibitor:
(e) Enzyme inhibitor:
(f) Receptor inhibitor:
(g) Prodrug:
Choices: Agonist, amphotericin B, antagonist, calicheamicin, ethidium bromide, folic acid, mechlorethamine,
prontosil, QSAR, SAR, sulfanilide, none of these.
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