1559r.ah15276-29011/02/0520:24Page279 Solutions to Problems CH, call t COOH d Name is acceptable.(IUPAC:3-(1-methylethyl)-benzenecarboxylic acid CH(CH) NH. Wrong numbers:3.4-dibromoaniline or 3.4-dibromobenzenamine. -(4-methoxnitophenyDethanone oacetophenone or 36 ene would be higher in energy by about 30 kcal mol-,so H would be-819 kcal mol- 7 7.40 nd 8 are deshielde they are closer to the other benzene ring in around the whole molecule(1).therin current of their own benzene ring ()and the ring curent of the adjacent benzene ring (iii): es co od The hydrogens at carbons 2,3,6,and 7 are too far away to feel a significant amount of the ring current of the other benzene ring.(c) Name is incorrect. Never mix o, m, p with numbers; call it 1,2-dimethyl-4-nitrobenzene. (d) Name is acceptable. (IUPAC: 3-(1-methylethyl)-benzenecarboxylic acid) (e) Wrong numbers; 3,4-dibromoaniline or 3,4-dibromobenzenamine. (f) Use only numbers: 4-methoxy-3-nitroacetophenone or 1-(4-methoxy-3-nitrophenyl)ethanone. 36. Benzene would be higher in energy by about 30 kcal mol1 , so Hcomb would be 819 kcal mol1 . 37. The hydrogens at carbons 1, 4, 5, and 8 are deshielded because they are closer to the other benzene ring in the molecule. They feel the deshielding effects of
-electron ring currents three ways: the ring current around the whole molecule (i), the ring current of their own benzene ring (ii), and the ring current of the adjacent benzene ring (iii): The hydrogens at carbons 2, 3, 6, and 7 are too far away to feel a significant amount of the ring current of the other benzene ring. H H (i) (ii) (iii) H H8 H1 H5 H4 H 7.77 7.40 NO2 CH3O CCH3 O NH2 Br Br CH(CH3)2 COOH NO2 CH3 CH3 Solutions to Problems • 279 1559T_ch15_276-290 11/03/05 20:24 Page 279