STEROIDS AND RELATED PRODUCTS: XIV. THE SYNTHESIS OF 17α-HALOGENATED 20,21-KETOLS OF THE CORTICOID TYPE

Abstract

In continuation of previous work, the hindering effect of 17α-substituents on replacement reactions in position 21 of the steroid molecule was further studied. It is shown that the impossibility of replacing a 21-halogen substituent by an acetoxy group in the presence of a bromine atom in position 17α is due both to a steric effect of the bulky 17-substituent and to its facile elimination. It is further shown that the replacement reaction in 21 may be carried out in the presence of the smaller and less readily eliminated 17α-chlorine substituent. In connection with these investigations, 17α-chloro-11-dehydrocorticosterone, the 17-chloro analogue of cortisone, was synthesized. The introduction of a chlorine atom into position 17 lowers the glucocorticoid activity.