1990 年 38 巻 1 号 p. 49-54
Thermolysis of 1-aryl-3-benzyl-1-nitrosoureas(1c, d) was carried out in CCL4 at 33°C under an atmosphere of air or argon, Decomposition of 1c, d under aerobic conditions gave mainly benzyl isocyanate (4b) via a diazoester intermediate, whereas under anaerobic conditions, decomposition gave 1-aryl-3-benzyl-3-nitrosoureas (5c, d) as 1, 3-shifted products, and 3-benzyl-1-(4-substituted 2-nitrophenyl)-3-nitrosoureas (8c, d) as transnitrosated products via N-NO bond cleavage, 3-Benzyl-1-(4-substituted 2-nitrophenyl)ureas (6c, d) were also produced by N-NO bond cleavage. The 1, 3-nitroso shift and transnitrosation under these conditions were assumed to involve a nitrosyl radical fission pathway. The nitrosated nitro compounds (8c, d) were also obtained together with 6c, d by nitration of the ureas (7c, d) with a mixture of fuming nitric acid and acetic acid. The N-nitrosourea (1c) acted as a nitrosating agent on 3-methyl-1-(4-tolyl)urea (7a) to convert it into nitrosoureas (1a and 5a).From our results, we presumed that the O-nitrosoisourea (11) or its isomer (12) was an intermediate in the 1, 3-nitroso shift and also an ultimate nitrosating agent in the transnitrosation reaction.
