Synthesis and Reactions of 1-Alkyl-3-(o-carbalkoxyphenyl)-triazenes

Abstract

The reaction of diazotized anthranilate esters with primary aliphatic amines has been reinvestigated, giving rise to a new series of comparatively unstable 1-alkyl-3-(o-carbalkoxyphenyl)-triazenes (3). The structures of the products have been confirmed by spectroscopic analysis, molecular ion mass measurements, and from the results of chemical degradation. The spectroscopic properties indicate a preference for the tautomer in which the azo-group is non-conjugated with the benzene ring, Ar•NH•N=N•R; this hypothesis is partly supported by the chemical degradation. In general, the triazenes (3) break down by fragmentation of the triazene moiety to give anthranilic acid derivatives, or undergo cyclization to 3-alkyltriazinones (1). The alkyltriazinones are also obtained directly in the coupling reaction of the diazonium salt with the amine in the presence of a sodium acetate buffer. The cyclization is quantitative when catalyzed by activity V alumina; a wide variation in the product distribution obtained by reaction with different types of alumina has been observed, and the correlation of these results with the known surface structure of alumina is discussed. Finally, an explanation is offered for the difference between the results of the present work and previous reports.