Synthesis of some novel 4-amino-4H-1,2,4-triazole-3-thiol derivatives

A novel series of pyrazolyl[1,2,4]triazoles has been synthesized by the reaction of polyfunctionalized-triazole 1 with symmetric and asymmetric β-dicarbonyl compounds in ortho-phosphoric acid. Also, we found that the reaction between triazole 1 and arylidene malononitriles in DMF afforded Schiff base compounds 9a,b instead of the target pyrazolyl[1,2,4]triazole 8a,b. The same products 9a,b were synthesized via the reaction of triazole 1 with the corresponding aromatic aldehydes. Moreover, a new series of 6-methyl-6-aryl-5,6-dihydro[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine-3-thiol 11a,b and 9-amino-5-methyl-3,5-diphenyl-8-sulfanyl-2,4,5,9-tetrahydro-3H-[1,2,4]triazolo[5,1-c][1,2,4]triazepin-3-ol 12a has been successfully synthesized by the reaction of triazoles 1 with acetophenone derivatives.