Phase transfer catalyzed synthesis and bioactivity of s-triazolo[3,4-b]thiadiazoles

A series of 3-(3-pyridyl)-6-substituted-s-1,2,4-triazolo[3,4-b]thiadiazoles was synthesized in good yields via condensation of 3-(3-pyridyl)-4-amino-5-thio-1,2,4-thiazoles with carboxylic acids in the presence of POCl3 and phase transfer catalyst tetrabutylammonium iodide (TBAI). The structures of the target compounds were confirmed by IR, H-1 NMR, MS and elemental analyses, and the in vitro activity was also evaluated.