Process for the preparation of Delta 9(11)- and delta 16-21-chloro-20-keto steroids of the pregnane and D-homopregnane series and their use as intermediates for the synthesis of highly effective corticoids.

摘要

DELTA <1><6> and DELTA <1><7>-21-chloro-20-keto steroids of the formula <CHEM> wherein n is 1 or 2, C1@C2 and C9@C11 represents a CC-single or CC-double bond, R1 is H or OH, R2 is H or CH3, R3 is H or F wherein, when R3 = F, C9@C11 is a CC-single bond, and R4 is H, CH3, or F, are valuable intermediates for preparation of highly effective, known steroids. A process for preparing these compounds involves heating the corresponding 11 beta - and/or 17 alpha - or l7a alpha -nitrooxy-21-mesyloxy-20-keto steroids with lithium chloride in a dipolar aprotic solvent at temperatures above room temperature.