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(CHEM111)[2005](f)final~2906^_76648.pdf
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CHEM111 FINAL EXAM (Fall 2005)

Name: Key (English) Key (Chinese)
Student ID No.
Problem Value Score.
1 2 3 4 5 6 7 8 9 10 30 60 20 60 60 10 40 80 50 40

...............
Total 450
Note: This is a close-book examination. You are required to answer ALL questions. Please write answers on the exam. Use blank space as scratch paper. Maximum time is 180 min.
1. Name the configuration of the chiral carbons in the following compounds: (30 pts)
(1)
H HO (2) HO

HO OH N CH3
OHH HO
-Glucose Morphine
C1: S ; C2: R ; C1: R; C2: R ;
C3: S ; C4: S ; C3: S; C4: R;
C5: R .
C5: S . 3 pts each configuration.
2. Multiple choices. There is only one correct answer for each of the following questions. (60 pts)
1) Compounds A and B are enantiomers. Which of the following statements is
INCORRECT: ( E )

A. They have the same melting points
B. The absolute value of their specific rotation is the same
C. It needs to involve bond breakage and reformation to change one into the other
D. A mixture of the two isomers in 1:1 molar ratio does not have optical activity
E. A mixture of the two isomers in 1:1 molar ratio is identical in melting point to either compounds
2) Compounds A and B are diastereomers. Which of the following statements is
CORRECT: ( C )

A. They have the same melting point
B. A mixture of the two isomers in 1:1 molar ratio is optically active
C. It needs to involve bond breakage and reformation to change one into the other
D. They have the same melting points
E. At least one of them has a chiral center
3) An alcohol and a thiol differ only in the functional groups OH and SH in their structures. Which of the following statement is CORRECT: ( B )
A. The alcohol is more acidic
B. When deprotonated, the thiol is higher in nucleophilicity
C. The thiol is higher in boiling point
D. The alcohol is more easily oxidized
E. Both compounds have pleasant smell like beer
4) Yeast alcohol dehydrogenase catalyzes a reaction as shown below. Which prochiral hydrgoen at carbon-1 in ethanol is removed by the NAD+? ( A )
A. pro-R hydrogen
B. pro-S hydrogen
OH

D
Alcohol dehydrogenase
C. si hydrogen
D. re hydrogen E. None of the above
DH

NAD
+ NADH
O

5) Yeast alcohol dehydrogenase also catalyzes the reverse reaction as shown in 4). In another word, it catalyzes a reaction as shown below. From which prochiral side of the carbon-1 in acetaldehyde does the hydride (:H-) from NADH attack? ( C )
A. pro-R side
B. pro-S side
D Alcohol dehydrogenase
OH
C. si face
D. re face

E. None of the above
O NADH NAD+ DH

6) A carbocation has the lowest energy level in which of the following solvents? ( C )
A. Methanol
B. Ethanol
C. Water
D. 50% Methanol + 50% water
E. 50% Ethanol + 50% water
7) How many configurational stereoisomers does the following compound (itself included) have