GB747097A - Steroids - Google Patents

Abstract

The invention comprises 3,11-beta-dihydroxy-pregnane-20-one-ketals of the general formula <FORM:0747097/IV(a)/1> wherein R represents hydrogen or an alkyl radical containing up to 6 carbon atoms and n is 1 or 2, and the preparation thereof by mixing the corresponding 11-keto compound with lithium aluminium hydride, sodium borohydride or lithium borohydride in an inert organic solvent at a temperature below about 100 DEG C., and then decomposing the complex reaction product by a known method. The preferred reaction temperature range is between about 0 DEG and about 80 DEG C. Suitable solvents referred to are ether, benzene, tetrahydrofuran and dioxan, and mixtures thereof. When the borohydrides are used for the reduction, the solvent may be an alcohol such as methanol, ethanol and isopropyl alcohol, and mixtures thereof, and aqueous organic solvents such as dioxan-water and alcohol-water mixtures. The process may be modified in that the 3-hydroxy-11,20-dione-20-ketal reactant is prepared by heating 3-hydroxypregnane-11,20-dione and an alkane diol of the general formula <FORM:0747097/IV(a)/2> wherein n and R have the above significance, in the presence of an acid catalyst. The group R may be a methyl, ethyl, propyl, isopropyl, butyl, 1-methylpropyl, amyl or hexyl group. In the examples the following compounds are prepared 3a ,11b - dihydroxypregnane - 20 - one - 20 - ethylene glycol ketal and the corresponding compounds where the ketal group is derived from propane-1,2-diol, hexane-1,2-diol, octane-1,2-diol and propane-1,3-diol, and 3b ,11b -dihydroxypregnane - 20 - one - 20 - ethylene glycol ketal. The preparation of the intermediate compound 3a -hydroxypregnane-11,20-dione - 20 - one - 20 - ethylene glycol ketal by the method referred to above is described. Similar intermediate and final compounds are referred to wherein the ketal groups are derived from butane-1,2-diol, 3-methylpentane-1,2-diol, hexane-1,2-diol, heptane-1,2-diol, octane-1,2-diol and pentane-1,3-diol. Specification 747,096 is referred to.