Improvements in the production of pseudo-sapogenin compounds

Pseudo-sapogenin esters are prepared from steroidal sapogenins or esters thereof by treatment with a mixture of a tertiary base and an esterifying agent at a temperature not exceeding 150 DEG C., and in the presence of a hydrogen halide or a substance capable of yielding a hydrogen halide under the conditions of the reaction, e.g. phosphorus oxychloride, acetyl chloride, or thionyl chloride. The hydrogen halide can be provided as the hydrohalide of an organic base, particularly of the tertiary base used in the reaction, e.g. pyridine, quinoline, picoline, collidine or lutidine. Specified esterifying agents are acetic, propionic, butyric and succinic anhydrides and the corresponding acid halides; and specified starting sapogenins are diosgenin, hecogenin, sarsasapogenin, chlorogenin, rockogenin and tigogenin, and their esters, especially formates, acetates, propionates, butyrates, benzoates, and trichloroacetates. In examples (1) diosgenin acetate is refluxed with pyridine and benzoyl chloride to yield pseudo-diosgenin 3-acetate - 26 - benzoate, which is then oxidized with chromic acid to D 5,16-pregnadien-3-ol-20-one, and also saponified with alcoholic potassium hydroxide to the free diol, which is then isomerized to diosgenin with hydrochloric acid in alcohol; (2) hecogenin acetate is refluxed with acetic anhydride and pyridine containing hydrogen chloride to yield pseudo-hecogenin diacetate; (3) diosgenin in pyridine is heated with propionic anhydride and methylamine hydrochloride, and the resulting pseudo-diosgenin dipropionate separated from its mixture with diosgenin propionate using acetone; (4) pseudo-diosgenin diacetate is prepared as in (1) by refluxing diosgenin with acetic anhydride and various tertiary bases, the hydrogen halide being supplied by use of thionyl chloride, phosphorus oxychloride, concentrated hydrochloric acid, acetyl chloride, hydrobromides of ethylamine, aniline, and diethylamine, or hydrochlorides of pyridine, methylamine diethylamine and trimethylamine.