65. How many positive and negative peaks appear in the DEPT-135 and in the DEPT-90 spectrum of 2-methylpentane? 

(A) DEPT-135: two positive and one negative, DEPT-90: one positive 

(B) DEPT-135: three positive and two negative, DEPT-90: one positive 

(C) DEPT-135: three positive and two negative, DEPT-90: no signals

 
(D) DEPT-135: two positive and three negative, DEPT-90: two positive 

(E) None of the above is correct

【單選題】每題 2 分，共計 40 分，答錯 1 題倒扣 0.5 分，倒扣至本大題零分為止，未作答，不給分亦不扣分。61. A student measured the optical activity of an unknown sugar at two different concentrations. The results of his measurements are shown below. Given that the sample cell had a path length of 10.0 cm, calculate the specific rotation for the unknown sugar.concentration                               observed rotation2.00 g sugar in 10.0 mL water              +159.1°  5.00 g sugar in 10.0 mL water              +127.8° (A) -10.5° (B) +25.6° (C) +79.5° (D) -104.5° (E) +256.2°

62. Which of the following series of synthetic steps could be used to carry out the transformation shown below?  (I) H2, Pt, (II) B2H6, (III) NaNO2, H3O , (IV) NaCN, HCl, (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

63. What is the major product of the following reaction? H2SO4 ?  (A) I (B) II (C) III (D) IV (E) V

64. Which of the following sequences efficiently converts 2-methylpropene into 3-methylbutanal? (A) 1) HBr; 2) NaCCH; 3) O3; 4) H2O (B) 1) HBr; 2) NaCCH; 3) O3; 4) DMS(C) 1) HBr, ROOR; 2) NaCCH; 3) O3; 4) H2O (D) 1) HBr, ROOR; 2) NaCCH; 3) H2/Ni2B; 4) O3; 5) DMS (E) 1) NaCCH; 2) H2/Ni2B; 3) O3; 4) DMS  

66. The Fischer indole synthesis is the reaction of phenylhydrazine with a carbonyl compound to give the corresponding indole. For the preparation of the following indole, what carbonyl compound is needed?  (A) I (B) II (C) III (D) IV (E) V

67. What is the major product obtained from the following reaction sequence?  (A) I (B) II (C) III (D) IV (E) V

68. Which of the following compounds can adopt a chair conformation in which there are no axial methyl groups?(A) 1,1-dimethylcyclohexane(B) cis-1,2-dimethylcyclohexane (C) trans-1,2-dimethylcyclohexane (D) trans-1,3-dimethylcyclohexane (E) everyone above have no axial methyl group

69. For the following reaction sequence, which molecule is an expected major product? 

70. Which of these is NOT a useful method for the synthesis of 1,3-pentadiene?(A) 1,4-pentanediol + H2SO4 at 180o C (B) 2,4-dibromopentane + (CH3)3COK , (CH3)3COH at 75o C (C) 2,4-pentanediol + H2SO4 at 180o C (D) HC=CCH=CHCH3 + H2, Ni2B (P-2)(E) 1,4-dibromopentane + CH3CH2ONa , CH3CH2OH at 75o C

71. Which of the following series of synthetic steps could be used to carry out the transformation shown below? (I) NaOH, (II) heat, (III) CH3COCH2COOEt, EtONa, (IV) NaOH, heat, then HCl, H2O (A) I → II → III → IV (B) IV → II → I → III (C) III →IV → II → I (D) II → IV → III → I (E) None of the above