| 摘要 |
A process for the preparation of a compound of the formula (A): <IMAGE> (A) wherein: R3 is a C1-5 alkyl group, a C3-6 alkenyl group, a C3-6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety contains 1 to 3 carbon atoms and the phenyl moiety is optionally substituted; R4 is a hydroxyl group, or a group OR6 wherein R6 is a C2-7 acyl group, a C1-4 alkyl group, or an optionally substituted benzyl group; R5 is hydrogen or a C1-5 alkyl group; or R4 and R5 together with the carbon atom to which they are joined represent a carbonyl group; which process comprises the reaction of a compound of the formula (C): <IMAGE> (C) wherein Q is a carbonyl group protected by a reagent capable of selectively protecting the 3-carbonyl of androstenedione, and R3, R4 and R5 are as defined in formula (A), to generate an unprotected carbonyl group in place of the protected carbonyl group Q. This process has advantages over the known process for the preparation of compounds of formula (A). |
