The invention relates to a method of preparing .DELTA.5,7-steroids, in particular 7-dehydrocholesterol compounds, of the general formula: ##STR1## wherein R is a hydrogen atom, a hydroxy group, optionally etherified with a C.sub.1 -C.sub.4 alkanol or esterified with a C.sub.1 -C.sub.4 alkane carboxylic acid, a C.sub.2 -C.sub.5 alkanoyl group, optionally ketalized with a C.sub.1 -C.sub.4 alkanol, or a branched or non-branched, saturated or unsaturated C.sub.1 -C.sub.10 alkyl group, optionally substituted with one or more fluorine atoms or hydroxy groups, which hydroxygroup or groups is (are) optionally etherified with C.sub.1 -C.sub.4 alkanol(s) or esterified with C.sub.1 -C.sub.4 alkane carboxylic acid(s), and R.sup.1, R.sup.2 and R.sup.3 are equal or different and represent hydrogen atoms or hydroxy groups, optionally etherified with C.sub.1 -C.sub.4 alkanols or esterified with C.sub.1 -C.sub.4 alkane carboxylic acids, or wherein R.sup.1 and R.sup.2 together constitute a C.sub.2 -C.sub.4 alkylene dioxy group, by dehydrobrominating 7-bromo-.DELTA.5-steroids under the influence of a fluoride as a base in an organic solvent.
本发明涉及一种制备.DELTA.5,7类
固醇的方法,特别是一般式为:##STR1## 其中R是氢原子,羟基,可选择与C.sub.1-C.sub.4烷醇醚化或与C.sub.1-C.sub.4烷基
羧酸酯化的羟基,C.sub.2-C.sub.5脂肪酰基,可选择与C.sub.1-C.sub.4烷醇进行
缩酮化,或支链或非支链,饱和或不饱和的C.sub.1-C.sub.10烷基,可选择用一个或多个
氟原子或羟基进行取代,其中羟基或羟基可选择与C.sub.1-C.sub.4烷醇醚化或与C.sub.1-C.sub.4烷基
羧酸酯化,而R.sup.1,R.sup.2和R.sup.3相等或不同,代表氢原子或羟基,可选择与C.sub.1-C.sub.4烷醇醚化或与C.sub.1-C.sub.4烷基
羧酸酯化,或其中R.sup.1和R.sup.2共同构成C.sub.2-C.sub.4烷基二氧基基团,通过在有机溶剂中以
氟化物作为碱的作用下脱
溴7-
溴-.DELTA.5-类
固醇。