| 摘要 |
1,141,074. 17α,21-Dihydroxy-20-keto-steroids preparation. CIBA Ltd. 20 June, 1966 [9 July, 1965; 6 April, 1966], No. 27460/66. Headings C2C and C2U. 17α,21 - Dihydroxy - 20 - keto - steroids are prepared by treating 17,20; 20,21-bis methylenedioxy steroids with a solution obtained by mixing anhydrous hydrogen fluoride with a carbamic acid or thiocarbamic acid or an amide or ester thereof. If the starting material further contains epoxide and/or ketal groupings these are respectively converted to fluorohydrin and oxo groupings in the process. The starting material may be a ring-modified steroid, such as an A-nor-B-homo-steroid and it may contain further substituents and double bonds. 3,6 - Dioxo - 11# - hydroxy - 17α,20; 20,21- bismethylenedioxy - A - nor - B - homo - #<SP>1</SP>- pregnene is prepared by condensing oxalic acid dimethyl ester with 3-oxo-4,5-oxido- 11#-hydroxy - 17α,20; 20,21 - b.m.d. - pregnane to give the 2-oxalic acid ester derivative, converting this to 3-oxo-4,5-oxido-11#-hydroxy-17α,20; 20, 21-b.m.d.-#<SP>1</SP>-pregnene and irradiating a solution of this and lithium carbonate in dioxan. |
