Steroids. XXXVI. Desulfurization Experiments in the 7-Ketopregnane Series

Abstract

7,ll-Diketones of the steroid series represent important intermediates in several syntheses of 11-oxygenated steroids from ring-C unsubstituted precursors and the removal of the 7-keto group is usually the penultimate step. I n a number of instances (1-3) this is accomplished by formation of the cycloethylene mercaptol followed by Raney nickel desulfurization according to the procedure first introduced into the steroid series by Rauptmann (4). At the present time, the C-11 oxygen introduction methods have been applied only to ring-C unsubstituted steroids with the alZo configuration a t C-5 (a). Since the corresponding saturated "normal" (5 P ) and A*-unsaturated 11-oxygenated derivatives are of very considerable importance and might possibly be obtainable from the intermediate 7,ll-diketones of the d o series, there were carried out certain model experiments with A5-pregnene-3p , 20p-diol-7-one diacetate (I) in order to study

Unsymmetrical 1,6-Additions To Conjugated Systems

“…The same product results in 45 per cent yield when the starting material is 3/3,20/3-diacetoxypreg-5-en-7-one (XXI), the first step being the elimination of acetic acid to form XIX, followed by addition of benzyl mercaptan. No assignment of configuration was made for the 3-benzylmercapto group (65).…”