WES-1 (Compound 8g) is an inhibitor of carbonic anhydrase IX ( K i : 55.9 μM). WES-1 has broad spectrum anti-proliferative activity against the cancer cells, such as leukemia (K-562 and MOLT-4), non-small cell lung cancer (NCI–H460), colon cancer (HCT 116 and HCT-15) and melanoma (LOX IMVI) cell lines.