| 摘要 |
<p>The invention relates to a method of preparing .DELTA. 5,7-steroids, in particular 7-dehydrocholesterol compounds, of the general formula wherein R is a hydrogen atom, a hydroxy group, optionally etheri fied with a C1-C4 alkanol or esterified with a C1-C4 alkane carboxylic acid, a C2-C5 alkanoyl group, optionally ketalized with a C1-C4 alkanol, or a branched or non-branched, saturated or unsaturated C1-C10 alkyl group, optionally substituted with one or more fluorine atoms or hydroxy groups, which hydroxygroup or groups is (are) optionally etherified with C1-C4 alkanol(s) or esterified with C1-C4 alkane carboxylic acid(s), and R1, R2 and R3 are equal or different and represent hydro gen atoms or hydroxy groups, optionally etherified with C1-C4 alkanols or esterified with C1-C4 alkane carboxylic acids, or wherein R1 and R2 together constitute a C2-C4 alkylene dioxy group, by dehydrobrominating 7-bromo-.DELTA.5-steroids under the influence of a fluoride as a base in an organic solvent.</p> |
