Methylation and Amination of 4H-[1,2,3]Triazolo[4,5-c][1,2,5]oxadiazole Salts

Methylation and amination reactions of 4Н-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazole salts (K⁺, Ag⁺, Et₃NH⁺, DBUH⁺) have been studied for the first time. It has been shown that the reaction of these salts with MeI results in two methylation products: K and Et₃N salts produce 4- and 5-isomers in equal amounts, while Ag and DBU salts form mainly 4-isomer. It has been found that the main amination product of K and DBU salts of 4Н-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazole with O-(p-tolylsulfonyl)hydroxylamine is 4-azido-3-amino-1,2,5-oxadiazole. A mechanism of its formation via rearrangement of 5-amino-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazole has been proposed.