531 1
served by BattisteZ2for six nonplanar phenyl groups in hexaphenyltropenylium ion. (22) M. A. Battiste and T. J. Barton, Abstracts, 152nd National Meeting of the American Chemical Society, New York, N. Y., Sept 13, 1966.
Kenneth M. Harmon, Ann B. Harmon, Brent C. Thompson Department of Chemistry, Haroey Mudd College Claremont, California 91711 Receiced August 10, 1967
Cleavage of Sulfonamides with Sodium Naphthalene' Sir: We wish to report that regeneration of amines from many types of sulfonamides can be achieved in excellent yield by treatment with sodium naphthalene anion radical in 1,2-dimethoxyethane solution. The pro-
ethane than in tetrahydrofuran solution. Dimethoxyethane does react slowly with sodium naphthalene4 but the process is slow enough at room temperature that it does not interfere with the cleavage reaction, From Table I it can be seen that benzene- and p toluenesulfonamides of most simple amines are cleaved in yields of over 90%, but methanesulfonyl derivatives exhibit variable behavior. In particular, it appears that methanesulfonamides of primary or aliphatic amines are inert to the cleavage conditions. Toluenesulfonamides of some simple dipeptides have been cleaved in good yield by this technique (see Table I), and the method may be of use in peptide synthesis, The well-known ease of N-alkylation of sulfonamides of primary amines5 also makes possible a relatively simple synthesis of a wide variety of pure secondary amines.
Table I. Cleavage of Sulfonamides with Sodium Naphthalene0 Sulfonamide (mp, "C)
Yield of amine, Z b s c
N-p-Tolylbenzene99 N-Methyl-N-phenylbenzene- 100 N-Octylbenzene97 (52.5-53.5 N-p-Tolyl-p-toluene87 88 Sodium salt (>300")' N-p- Anisyl-p-toluene98 N-Phenyl-p-tolueneN-Hexyl-p-toluene- (59-60')L N-Octyl-p-toluene98 N-(2-Heptyl)-p-toluene(oil)g N-( 1-Phenylethy1)-p-toluene(82-83 ")" N-(m-Chloropheny1)-ptolueneN-Methyl-N-phenyl-ptoluene96 N-pToluenesulfony1piperidine 82
(86)d (65) (93)d (94)d (97) (96)d (95) (91) (98) (94)h (68)$
Sulfonamide (mp, "C)
N-p-Tolyl-p-chlorobenzene N-Meth yl-N-phenyl-pchlorobenzene- (95-95.4")6 N-p-Tolyl-p-bromobenzeneN-p-Tolyl-p-acetamidobenzeneN-p-Tolyl-p-methoxybenzene- (109.5-110")6 N-Methyl-N-phenyl-pmethoxybenzene(109-110.3)"
N-p-Tolyl-@-naphthaleneN-Methyl-N-phenyl+ naphthalene(102-102.6")e N-Octyl-a-toluene(100- 10I 0)" N-a-Toluenesulfonylpiperidine (137.5-1 38 ")"
Yield of amine, % b , c 89 67 89 80 95 (83) 92 89 (93)d 91
84 62
Sulfonamide (mp, "C) N-Octylmethane(56.3-56.6")" N-p-TolylmethaneN-MethanesulfonyIpiperidine (48.5-50")1 N- Methyl-N-phenylmethaneN,N-Diphenylmethane(1 16.5-1 17") e N-p-Toluenesulfony lglycylglycine N-p-Toluenesulfonyl-DLalanyl-DL-leucinek'2 N-p-Toluenesulfonyl-DLleucyl-DL-alaninek , m N-p-Toluenesulfonyl-DLalanyl-DL-valine (188-190 ")k N-p-Toluenesulfonyl-DLalanyl-DL-phenylalanine 1167-168 "Y
Yield of amine, z b 8 c
