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

69. Which one of the following reactions would give the product as it is planned? (A) (B)  (C) (D) (E)

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

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