Part I (10 marks) - Multiple Choice (1 mark each) Place your answers in the boxes on the
answer sheet.
A. The structure of codeine, an alkaloid which is a derivative of opium and a drug which has
been used for centuries as a pain-killer and sedative, is shown below. Questions 1 to 2 pertain to
this structure.
↑
1. How many possible stereoisomers of codeine are there?
(a) 16 (b) 5 (c) 32 (d) 64 (e) 8
2. What is the configuration of the atom labeled “a” in the codeine structure?
(a) R (b) S (c) E (d) Z (e) not a stereocenter
3. Which is the best nucleophile in methanol?
(a) Br-
(b) NH3
(c) CH3S-
(d) CH3O-
(e) HO-
4. Rank the following in INCREASING acidity:
(a) A>B>C
(b) C>B>A
(c) B>A>C
(d) C>A>B
(e) A>C>B
5. Which of the following statements is TRUE regarding the reaction below?
, I- The mixture of products formed is optically active.
II-The stereoisomer shown is a meso compound.
III- The stereoisomer shown has a (1R, 2S) configuration.
IV-The stereoisomers formed are diastereomers relative to each other.
V-The stereoisomers are formed in a 50:50 ratio.
(a) I and IV only
(b) II, IV and V
(c) III, IV and V
(d) I, II, and IV
(e) I, III and IV
6. Which of the following mechanisms does NOT contain an error?
a)
b)
c)
d)
answer sheet.
A. The structure of codeine, an alkaloid which is a derivative of opium and a drug which has
been used for centuries as a pain-killer and sedative, is shown below. Questions 1 to 2 pertain to
this structure.
↑
1. How many possible stereoisomers of codeine are there?
(a) 16 (b) 5 (c) 32 (d) 64 (e) 8
2. What is the configuration of the atom labeled “a” in the codeine structure?
(a) R (b) S (c) E (d) Z (e) not a stereocenter
3. Which is the best nucleophile in methanol?
(a) Br-
(b) NH3
(c) CH3S-
(d) CH3O-
(e) HO-
4. Rank the following in INCREASING acidity:
(a) A>B>C
(b) C>B>A
(c) B>A>C
(d) C>A>B
(e) A>C>B
5. Which of the following statements is TRUE regarding the reaction below?
, I- The mixture of products formed is optically active.
II-The stereoisomer shown is a meso compound.
III- The stereoisomer shown has a (1R, 2S) configuration.
IV-The stereoisomers formed are diastereomers relative to each other.
V-The stereoisomers are formed in a 50:50 ratio.
(a) I and IV only
(b) II, IV and V
(c) III, IV and V
(d) I, II, and IV
(e) I, III and IV
6. Which of the following mechanisms does NOT contain an error?
a)
b)
c)
d)
