Potent, selective inhibitor of Cdc25 dual specificity phosphatases (Ki values are 29, 95 and 89 nM for human Cdc25A, Cdc25B2 and Cdc25C respectively); > 20- and > 450-fold selective over VHR and PTP1B phosphatases respectively. Arrests cells at both G1 and G2/M phase and blocks cdk2 and cdk1 activation. Blocks proliferation of a range of human tumor cell lines (IC50 = 0.2 - 35 μM). Purity 99%. MW (observed): 321.76