Synthesis and structure elucidation of 3-methoxy-1-methyl-1H-1,2,4,-triazol-5-amine and 5-methoxy-1-methyl-1H-1,2,4,-triazol-3-amine

Previously it was shown that condensation of dimethyl N-cyanodithioimidocarbonate (1a) with methylhydrazine gave predominantly 1-methyl-5-methylthio-1H-,2,4-triazol-3-amine (2), which was initially identified erroneously as the regioisomer l-methyl-3-methylthio-1H-1,2,4-triazol-5-amine (3). We have found that reaction of dimethyl N-cyanoimidocarbonate (1b) with methyl hydrazine affords a high yield of 3-methoxy-1-methyl-1H-1,2,4-triazol-5-amine (4) rather than the regioisomer 5-methoxy-1-methyl-1H-1,2,4-triazol-3-amine (5). The structure assignment of 4 was confirmed by X-ray crystallographic analysis of the benzenesulfonyl isocyanate adduct 7. Triazole 5 was obtained after reacting dimethyl N-cyanothioimidocarbonate (1c) with methylhydrazine.