Protein tyrosine phosphatase (PTP) 1B is a potential target for the treatment of diabetes and obesity. We have previously identified the benzoyl sulfathiazole derivative II as a non-competitive PTP1B inhibitor with in vivo insulin sensitizing effects. Preliminary SAR study on this compound series has been carried out herein, and thirteen new compounds have been designed and synthesized. Among them, compound 10 exhibited potent inhibition against human recombinant PTP1B with the IC50 value of 3.97 micromol x L(-1), and is comparable to that of compound II.