Сonvenient Access to 1,3-Dimethyl[1,2,4]Triazolo[3,4-b][1,3,4]-Thiadiazol-1-Ium and 7H-[1,2,4]Triazolo[4,3-b][1,2,4]Triazol-1-Ium Salts

 Methylation of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol with methyl iodide in sodium methylate afforded unexpected 4-amino-1,3-dimethyl-4H-1,2,4-triazole-5-thione. Reaction of the latter with phenylisothiocyanate gave 6-anilino-1,3-dimethyl[1,2,4]triazolo-[3,4-b][1,3,4]thiadiazol-1-ium hydrosulfide. Acid-catalyzed condensation of 4-amino-1,3-dimethyl-4H-1,2,4-triazole-5-thione with ethyl orthoformate in ethanol lead to the corresponding ethyl N-substituted (5-thioxo-1,5-dihydro-4H-1,2,4-triazol-4-yl)ethanimidoate derivative. Condensation of the latter with anilines or phenylhydrazine gave a group of new 7H-[1,2,4]triazolo[4,3-b][1,2,4]triazol-1-ium hydrosulfides.