2-Arylhydrazononitriles in heterocyclic synthesis: a novel route to 1,3-diaryl-1,2,4-triazol-5-amines via a Tiemann rearrangement of arylhydrazonoamidoximes

2-Arylhydrazononitriles react with hydroxylamine hydrochloride in refluxing ethanolic sodium acetate to yield amidoximes that cyclized into 1,2,3-triazol-5-amines or 1,2,4-triazol-5-amines depending on the nature of the substituents on hydrazone linkage. NOE difference experiments could successfully be utilized to distinguish 1,2,3-triazoles from isomeric 1,2,4-triazoles.