1559T_ch22.389-40910/19/0517:23Pag0404 404 chapter 22 CHEMISTRY OF BENZENE SUBSTITUENTS:ALKYLBENZENES,PHENOLS,AND BENZENAMINES 58.Compounds (a)through (d)require nitrosation (also calledn using NaNOHCl.C)to ?(CB o(ot CuCN.KCN. 5C(for CN).For (e)we are placing a than replacing the nitrogen with H;C 59.Think about benzenediazonium salts as intermediates likely to be useful in these NO COOH w HNO,.HSO. More COOH COOH NNOCHCLHOO. N2"CI OH [See Gadirect evidence that reversible dissociation of N2 to leave behind a phenyl cation can take place. This system is an example of how a seemingly simple structure can exhibit a lot of complexity in its behavior. 58. Compounds (a) through (d) require nitrosation (also called diazotization, using NaNO2, HCl, 0 C) to give the 3-methylbenzenediazonium salt, followed by treatment as appropriate for the final desired sub￾stituent: (a) H3PO2 (replaces N2 with H); (b) CuBr, 100 C (for Br); (c) heat (for OH); (d) CuCN, KCN, 50 C (for CN). For (e) we are placing a substituent on the nitrogen rather than replacing the nitrogen with something else. Specifically, the problem asks for the conversion of a primary amine into a secondary amine, which is best done by reductive amination (Section 21-6): 59. Think about benzenediazonium salts as intermediates likely to be useful in these. (a) (b) (c) Cl [See (a)] Cl N2 Cl OH HNO3, H2O, 0 C product H2O,  NO2 COOH N2 Cl COOH CuCN,  product 2. NaNO2, HCl, H2O, 0 1. H2, Ni, CH3CH2OH 2. KMnO4, HO 1. CH3CH2CH2Cl*, AlCl3 *More selective for monoalkylation HNO3, H2SO4,  COOH 1. H2, Ni 2. NaNO2, HCl, H2O, 0 C CuCl,  N2 Cl Br product HNO3, H2SO4 Br2, FeBr3 NO2 Br NO2 2. NaBH3CN H3C NH2 1. CH3CHO H3C NHCH2CH3 404 • Chapter 22 CHEMISTRY OF BENZENE SUBSTITUENTS: ALKYLBENZENES, PHENOLS, AND BENZENAMINES 1559T_ch22_389-408 10/19/05 17:23 Page 404