| 摘要 |
1322414 Preparation of 6α-alkyl-19-norsteroids ORGANON LABORATORIES Ltd 19 April 1971 [24 March 1970] 25199/71 Heading C2U #<SP>4</SP> - 3 - Keto - 6α - alkyl - 19 - nor - steroids are prepared in substantially quantitative yields by alkaline hydrolysis of #<SP>3,5</SP>-3-acyloxy-6-alkyl- 19-nor-steroids, prepared in turn, for example, by enol acylation of #<SP>4</SP>-3-keto-6#-alkyl-19-norsteroids which may contain some of the 6α- epimer, or by enol acylation with accompanying dehydration of 3-keto-5a-hydroxy-6#-alkyl-19- nor-steroids. Examples are given, and a comparative example describes the dehydration of 5α - hydroxy - 6# - methyl - estrane - 3,17 - dione to give a mixture of 6α- and 6#-methyl-#<SP>4</SP>- estrene-3,17-dione, conversion of this mixture to 3 - ethoxy - 6 - methyl - #<SP>3,5</SP> - estradien - 17- one and acid hydrolysis of this enol ether to yield the epimeric mixture of #<SP>4</SP>-3-ones again. |
