Treatment of the diazonium salts, X•C6H4N2+, with aqueous methylamine affords good yields of the monomethyltriazenes, X•C6H4•N=N•NHMe, when the substituent is a strongly electron-withdrawing group (X = o-, m-, and p-NO2; o-, m-, and p-CO2R; p-CN and p-COCH3). Preparation of the triazene from the p-bromobenzene diazonium salt was accompanied by formation of a pentaazadiene. Monomethyltriazenes were not obtained when diazonium salts containing other substituents (X = H, p-CH3, o-CF3, p-Cl, p-F, p-NMe2, p-OH, p-OCH3, p-Ph, p-NHCOCH3) were treated with methylamine. In these cases the products were either pentaazadiene, or 1,3-diaryltriazenes or unstable materials. The monomethyltriazenes vary considerably in stability and give rise to a number of different degradation products, which were either diaryltriazenes or 3-alkyl-1,3-diaryltriazenes or simply arylamines. 1(3)-(p-Nitrophenyl)-3(1)-methyltriazene was found to be a moderately effective methylating agent.

Diazotization of 2′-aminoacetophenone, followed by coupling with primary aliphatic amines, affords unstable triazenes which readily undergo cyclodehydration over neutral alumina to give 3-alkyl-4-methylene-1,2,3-benzotriazines (5a-d). 3-Aryl-4-methylene-1,2,3-benzotriazines (8a-c) are likewise obtained by cyclodehydration of the stable 1-(ortho-acetylphenyl)-3-aryltriazenes (7a-c). Attempted synthesis of the unsubstituted 4-methylene-1,2,3-benzotriazine (5e), by the same method, did not succeed. 4-Hydroxy-1,2,3-benzotriazines (4) are postulated as intermediates in the cyclodehydration; this hypothesis is supported by the isolation of the stable 4-hydroxy-1,2,3-benzotriazine (12) from the coupling reaction of methylamine with the diazonium salt derived from ortho-aminobenzophenone. An account of a preliminary study of the thermolysis of 3-methyl-4-methylene-1,2,3-benzotriazine (5a) is included.

T. PATRICK AHERN, HANDRICK FONG, and KEITH VAUGHAN. Can. J. Chem. 54, 290 (1976). The synthesis of I-(0-carboxamidopheny1)-3-aryl triazenes 12 and 15 (X = CONH2 and H ) is described. [Tradilit par le journal]

Die als potentielle Ausgangsprodukte für die Synthese des Systems (V) angesehenen Triazene (III) werden aus Anthranilsäureamid (I) und den Diazoniumsalzen (II) dargestellt.

Diazotierung des Amins (I) und Kupplung mit den Aminen (II) führen zu instabilen Triazenen, die an Al2O3 leicht Cyclodehydratisierung unter Bildung der Titelverbindungen (IV) eingehen.