Estrone sulfamate (EMATE) is a potent irreversible inhibitor of steroid sulfatase (STS). In order to further expand SAR, the compound was substituted at the 2-and/or 4-positions and its 17-carbonyl group was also removed. The following general order of potency against STS in two in vitro systems is observed for the derivatives: The 4-NO2> 2-halogens, 2- cyano> EMATE (unsubstituted)> 17-deoxyEMATE> 2-NO2> 4-bromo> 2-(2-propenyl), 2-n- ...