Synthesis, Crystal Structure, and Antibacterial Activity of 1,2,4-Triazoles and 1,2,4-Triazol-3-one

A straightforward method has been developed for the synthesis of 1,2,4-triazol-3-one 3 and 1,2,4-triazoles 6a, 6b, 6c, 6d starting from N1-substituted-N1-tosylhydrazonates 2 and hydrazine monohydrate. This methodology affords a number of 1,2,4-triazol-3-one 3 and 1,2,4-triazoles 6a, 6b, 6c, 6d in reasonable yields. The structures of all new compounds were elucidated using infrared, 1H and 13C NMR, high-resolution mass spectrometry, elemental analysis, and the X-ray crystallography (for compounds 3 and 6a). Some of the newly synthesized compounds were screened for their antibacterial activity.