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.
1-芳基-3-苄基-1-亚硝基
脲(1c, d)的热解在33°C下于
四氯化碳中进行,反应气氛为空气或
氩气。在有氧条件下,1c, d的分解主要通过一个重氮酯中间体生成苄基
异氰酸酯(4b),而在缺氧条件下,分解生成1-芳基-3-苄基-3-亚硝基
脲(5c, d),作为1, 3转位产物,并通过N-NO键裂解生成3-苄基-1-(4-取代的2-
硝基苯基)-3-亚硝基
脲(8c, d),作为转亚硝基产物。同时,N-NO键的裂解也生成了3-苄基-1-(4-取代的2-
硝基苯基)
尿素(6c, d)。在这些条件下,1, 3-亚硝基转移和转亚硝基反应被假定涉及亚硝基自由基裂解途径。通过用烟雾
硝酸和
醋酸混合物对
尿素(7c, d)进行硝化反应,得到的亚硝化
硝基化合物(8c, d)也与6c, d一起获得。N-亚硝基
脲(1c)作为亚硝基化试剂对3-甲基-1-(4-
甲苯基)
尿素(7a)进行反应,将其转化为亚硝基
脲(1a和5a)。根据我们的结果,我们推测O-亚硝基异
脲(11)或其异构体(12)是在1, 3-亚硝基转移反应中的中间体,并且是转亚硝基反应中的最终亚硝基化试剂。