74. What is the major product of the following reaction? 
(A) 
(B) 
(C) 
(D) 
(E) None of the above

70. What is the major product of the following reaction? (A) I (B) II (C) III (D) IV (E) V

71. What is the major product of the following reaction? (A) I (B) II (C) III (D) IV (E) V

72. What is the major product of the following reaction? (A)  (B) (C)  (D) (E) None of the above

73. Which of the following series of synthetic steps could be used to carry out the transformation shown below?  I. H2, Pt/C II. B2H6 III. NaNO2, H3O IV. CH3NO2, KOH V. H2O2, NaOH VI. PCC (A) I → II → V (B) IV → I → III (C) III → VI → V (D) II → V → III (E) None of the above

75. What is the major product of the following reaction? (A)  (B) (C)  (D) (E) None of the above

76. What is the major product of the following reaction?  (A) (B) (C)  (D) (E) None of the above

77. How to prepare aspirin from phenol? (A) 1. NaOH, CO2 2. H3O 3. Ac2O (B) 1. CH3COCl, AlCl3 2. NaNO2, then H3PO2 3. H3O (C) 1. Ac2O 2. H3O 3. NaOH, CO2 (D) 1. HNO3, H2SO4 2. Fe, HCl 3. CH3COCl, AlCl3 (E) 1. Ac2O 2. NaOH 3. CO2, then H3O

78. What is the major product of the following reaction? (A) (B) (C) (D) (E)

79. 7-Dehydrocholesterol, a steroid found in skin, is converted into vitamin D3 by two pericyclic reactions. What are these two reactions? (A) 1. an electrocyclic reaction 2. an ene reaction (B) 1. a [1,7] sigmatropic rearrangement 2. an electrocyclic reaction (C) 1. an electrocyclic reaction 2. a [1,7] sigmatropic rearrangement (D) 1. an ene reaction 2. an electrocyclic reaction (E) 1. an ene reaction 2. a [1,7] sigmatropic rearrangement

80. What is the major product of the following reaction?  (A)  (B) (C) (D) (E) None of the above