SYNTHESIS AND REACTIONS OF MIXED BROMO-CHLORO 3-KETOSTEROIDS¹

Abstract

Our recently reported study (1) of chlorinated 3-ketosteroids, particularly of the 5a(alio) series, has demonstrated a marked difference in the behavior of these chloro ketones as compared to their bromo and iodo analogs towards reagents such as sodium iodide, collidine, and chromous chloride. It appeared of interest, therefore, to extend this investigation to mixed bromo-chloro 3-ketosteroids which should lend themselves to interesting, selective manipulations and the present paper is concerned with a description of such experiments. Since completion of this manuscript, there has come to our attention a very recent communication by Ellis and Petrow (2) bearing on the same subject. Wherever the work of the British workers parallels that of our past (1) and present papers, the results are in good agreement. SUMMARY 2,2-Dichlorocholestanone (I) can be dehydrochlorinated with collidine or 2,4-dinitrophenylhydrazine to A1-2-chlorocholesten-3-one (VIII) but it cannot be rearranged with hydrogen bromide to a 2,4-isomer. Chlorination of 2abromocholestanone (III) or bromination of 2a-chlorocholestanone (II) leads to