1,2,4-Triazoles. Improved Synthesis of 5-Substituted 4-Amino-3-mercato-(4H)-1,2,4-triazoles and a Facile Route to 3,6-Disubstituted 1,2,4-Triazolo[3,4-b][1,3,4]thiadiazoles

Article abstract of DOI:10.1002/jhet.5570340427

The reaction of thiocarbohydrazide with carboxylic acids at the melting temperature allows an improved preparation of the 5-substituted 4-amino-3-mercapto-1,2,4-triazole heterocycles. The crude 4-amino-5-mercapto-1,2,4-triazoles react easily with carboxylic acids or carboxylic acid chlorides to afford the 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole ring system.