| 摘要 |
<p>Novel steroids of the formulae <FORM:1092142/C2/1> (where X is H or halogen R1 is H, 11b -OH, 11b -chloro or keto but is chloro only when X is halogen and is H only when X is H; R2 is H, a -CH3 or a -F, R3 is H, a -or b -CH3 or = CH2; R4 is H, acyl, alkyl, 2-hydroxyethyl, aralkyl, aryl which may be substituted, cycloalkyl or heterocyclic; and R5 is H or acyl) and salts thereof and the corresponding 4,6-pregnadienes and 5a -pregnanes are prepared from the corresponding 2-unsubstituted-3-keto steroids via the 2-hydroxymethylene or 2-alkoxymethylene steroids by standard procedures, the 17-side chain being temporarily protected by b.m.d. group formation. The N-alkyl products may be prepared by direct alkylation of the N-unsubstituted compounds. The N-acyl-21-acylates are prepared from the N-unsubstituted 21-ols by acylation, and on heating with aqueous acetic acid the N-acyl group is selectively removed; both acyl groups are removed with sodium methoxide in methanol. The 9a -halo-11b -ols of the invention may also be prepared by oxidation to the 11-ones before pyrazole ring formation with subsequent reduction after the pyrazole ring is formed. 11b ,17a ,21 - Trihydroxy - 21 - methyl - 5a -pregnane-3,20-dione is prepared by hydrogenation of the D 4-pregnene. Other 5a -pregnanes are prepared similarly and D 4,6-pregnadienes are prepared by chloranil dehydrogenation.</p> |
