PTP1B inhibitors with the following structure (formula I). Experiments indicate that these inhibitors can effectively inhibit the activity of protein tyrosine phosphatase 1B (PTP1B). They can be used as insulin sensitisers. They can be used to prevent, delay or treat diseases which are related to insulin antagonism mediated by PTP1B, especially diabetes type II and obesity. The invention also provides methods for preparing these inhibitors.
