A Novel One-Pot Synthesis of 1,2,4-Triazole-3,5-diamine Derivatives from Isothiocyanates and Mono-Substituted Hydrazines.

1,2,4-Triazole-3,5-diamine derivatives were synthesized in moderate to high yields in one-pot reaction from the corresponding isothiocyanates, mono-substituted hydrazines, and sodium hydrogencyanamide, in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. Typically, two target compounds were obtained, but high regioselectivities to one isomer were observed when aromatic and sterically bulky hydrazines were used. A number of examples with a detailed representative procedure are given.