We investigated whether the benzophenone moiety can be used as core element of steroid sulfatase (STS) inhibitors. While 4-and 3-benzophenone-O-sulfamates inhibit STS with IC50 values between 5 and 7μM irrespective of additional hydroxy and methoxy substituents at the second phenyl ring, benzophenone-O, O′-disulfamates show increased activity. With an IC50 value of 190nM the 4, 4′-derivative is the first small monocyclic STS inhibitor ...