Novel sulfur-containing glutethimide derivatives, substituted with either thiol or methylsulfide groups in the ortho/paru positions of the aromatic ring, were synthesized and tested for both human placental aromatase and bovine adrenocortical desmolase inhibitory activities. The synthesis was achieved by the chlorosulfonation of gluthethimide, which yielded a 3: 1 mixture of the para to orrho sulfonyl chlorides 2ab. The sulfonyl chlorides of gluthethimide were reduced with Zn/H2S04 to give the thioglutethimides 3ab, which in turn were methylated with MeI/EtOH to give the corresponding methylsulfides 4ab. In comparison to aminoglutethimide (AG), 3a/b and 4ab were weak inhibitors of aromatase, with 3a/h being more potent tban 4ab. Aromatase inhibition by the thiol compound was pH-dependent; 3ab was most potent at higher pH (7.4) than at lower (6.6). This suggested that the thiolate form of 4 coordinates with the femc heme of aromatase. Likewise, both 3ab and 4ab were less potent at inhibiting bovine adrenal desmolase than AG. Possible reasons for the surprisingly poor arornatase inhibitor activity of t k s e compounds are discussed.