Synthesis and biological evaluation of novel thiadiazole amides as potent Cdc25B and PTP1B inhibitors

A novel series of thiadiazole amide derivatives have been synthesized and evaluated for inhibitory activity against Cdc25B and PTP1B. Most of them showed inhibitory activities against Cdc25B (IC50 = 1.18-8.01 μg/mL) and PTP1B (IC50 = 0.85-8.75 μg/mL), respectively. Moreover, compounds 5b and 4l were most potent with IC50 values of 1.18 and 0.85 μg/mL, respectively, which activities are comparable with reference drugs Na3VO4 (IC50 = 0.93 μg/mL) and oleanolic acid (IC50 = 0.85 μg/mL). The results of selectivity experiments showed that the target compounds were selective inhibitors against PTP1B and Cdc25B. Enzyme kinetic experiments demonstrated that compound 5k was a specific inhibitor with the typical characteristics of a mixed inhibitor.