3-Alpha-hydroxy-5 beta-pregnane-11,20-di:one prepn. - from desoxy-cholic acid via 3-alpha-acyloxy-alpha-11-cholene acid ester

摘要

The prepn. of 3 alpha-hydroxy-5 beta- pregnane-11,20- dione (I) from desoxycholic acid (II) comprises (a) converting (I) to the 24-ester; (b) acylating this ester in the 3-position and mesylating in the 11-position; (c) cleaving methane sulphonic acid from the resulting cpd. to give a 3 alpha- acyloxy-alpha 11-cholene acid ester. Process comprises (d) stereospecifically hydrating this ester to give 3-acyloxy-11 beta-hydroxy cholene acid; (e) saponifying this ester and oxidatively decarboxylating to give 3 alpha-acyloxy-11 beta-hydroxy -24-norchol-22-ene; (f) isomerising this to give 3 alpha-acyloxy-11 beta-hydroxy-24-norchol-20(22)- ene with simultaneous saponification of the 3-acyl gp.; (g) subjecting this prod. to ozone degradation, to oxidise the 11-OH gp. to a keto gp. Specifically claimed cpds. include 3 alpha-acyloxy- 12 alpha- iodo-11 beta-nitrate- cholene acid ester (III) 3 alpha-acyloxy- 11 beta- nitrato-cholane acid ester (IV), 3 alpha-acyloxy-12- alpha-iodo-11-oxo-dioleae acid ester (V) and 3 alpha-11 beta- diacyloxy -12 alpha-bromo cholane acid ester (VI). (I) is an inter in the prodn. of cpds. of the cortisone series. (III)-(VI) are all inters in the prodn. of (I).