A process for the preparation of a compound of the formula (A): ##STR1## wherein: R.sub.3 is a C.sub.1-5 alkyl group, a C.sub.3-6 alkenyl group, a C.sub.3-6 cycloalkyl group or an alkylphenyl group in which the alkyl moiety contains 1 to 3 carbon atoms and the phenyl moiety is optionally substituted; R.sub.4 is a hydroxyl group, or a group OR.sub.6 wherein R.sub.6 is a C.sub.2-7 acyl group, a C.sub.1-4 alkyl group, or an optionally substituted benzyl group; R.sub.5 is hydrogen or a C.sub.1-5 alkyl group; or R.sub.4 and R.sub.5 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): ##STR2## wherein Q is a carbonyl group protected by a reagent capable of selectively protecting the 3-carbonyl of androstenedione, and R.sub.3, R.sub.4 and R.sub.5 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).
一种制备式(A)化合物的方法:##STR1## 其中:R.sub.3是C.sub.1-5烷基,C.sub.3-6烯基,C.sub.3-6环烷基或含有1至3个碳原子的烷基苯基,苯基可以选择性取代;R.sub.4是羟基,或OR.sub.6基团,其中R.sub.6是C.sub.2-7酰基,C.sub.1-4烷基或选择性取代的苯甲基基团;R.sub.5是氢或C.sub.1-5烷基;或R.sub.4和R.sub.5与它们连接的碳原子一起表示羰基基团;该过程包括化合物(C)的反应:##STR2## 其中Q是由能够选择性保护
雄烯二酮的3-羰基的试剂保护的羰基基团,R.sub.3,R.sub.4和R.sub.5如式(A)中所定义,以生成未保护的羰基基团代替受保护的羰基基团Q。该过程比已知的制备式(A)化合物的方法具有优势。