A potent and selective antitumor agent that displays potent activity against renal, colon, and breast cancer cell lines in the NCI 60-cell panel. Shows potent antitumor activity in HCT 116 and HT 29 human colon as well as MCF 7 and MDA 468 human breast cancer cell lines. Also displays in vivo antitumor activity against human RXF 944XL renal xenografts in nude NMRI mice. Inhibits thioredoxin reductase with potencies correlated with their antiproliferative and cytotoxic efficacies. MW: 243.29. Purity ≥98% by HPLC