Part I (10 marks) - Multiple Choice (1 mark each) Place your answers in the boxes on the
A. The structure of doxorubicin, a drug widely used in chemotherapy and treatment of cancer, is
shown below. Questions 1 to 6 pertain to this structure.
1. How many sp3 hybridized quaternary carbon atoms are in doxorubicin?
(a) 2 (b) 5 (c) 0 (d) 1 (e) 12
2. The hybridization of the oxygen labeled “b” is
(a) sp (b) sp2 (c) sp3 (d) 2p (e) none of the above
3. The bond between carbons labeled “c” and “d” is formed by overlap of
which type of orbitals on these atoms?
(a) sp3(C “c”)-sp3(C “d”) (b) sp2(C “c”)-sp2(C “d”) (c) sp2(C “c”)-sp3(C “d”)
(d) sp3(C “c”)-sp2(C “d”)
4. How many degrees of unsaturation does doxorubicin have? (Molecular Formula: C27H29NO11)
(a) 7 (b) 5 (c) 13 (d) 9 (e) 14
5. Which best describes the two positions of the substituents on the carbons labeled “e” and “f”,
(a) axial, axial (b) equatorial, equatorial (c) axial, equatorial (d) equatorial, axial (e) none of
6. The shape at carbon atom labeled “a” can best be described as:
(a) trigonal planar (b) bent (c) trigonal pyramidal (d) linear (e) tetrahedral
B. Which of the following terms best describes the relationship of each pair of molecules
below? Answer questions 7 to 9 using one of the following 6 terms.
(a) constitutional isomers (b) identical molecules (c) cis/trans or E/Z isomers
(d) enantiomers (e) not related (different)
10. Which is the correct IUPAC name for the structure shown on the right?
Part i (10 marks) - multiple choice (1 mark each) place your answers in the boxes on the answer sheet: the structure of doxorubicin, a drug widely used in chemotherapy and treatment of cancer, is shown below. Answer questions 7 to 9 using one of the following 6 terms. (a) constitutional isomers (d) enantiomers (b) identical molecules (e) not related (different) (c) cis/trans or e/z isomers. Br: which is the correct iupac name for the structure shown on the right, 5-sec-butyl-4-cyclopropyl-7-methylnonane, 5-sec-butyl-6-cyclopropyl-3-methylnonane, 4-sec-butyl-5-cyclopropyl-2-ethyloctane, 5-sec-butyl-4-cyclopropyl-7-ethyloctane, 5-sec-butyl-7-ethyl-3-methylcyclopropane. Part ii: short answers (i) on the answer sheet, complete the partial structures for the two chair conformations of cis-1- bromo-4-sec-butylcyclohexane. (ii) on the answer sheet, complete the partial structures for the two chair conformations of trans- 1- bromo-4-sec-butylcyclohexane. (iii) designate which conformation (a or b) is more stable in both part (i) and (ii). (circle one for each on the answer sheet).