Selective inhibitor of protein-tyrosine phosphatase 1B (PTP1B) (Ki values are 0.29, 59, 560, 1100, > 2000, > 2000 and > 2000 μM for PTP1B, CD45 D1D2, PTPβ, PTPε D1, SHP-1, PTPα D1 and LAR D1D2 respectively).