GB783092A - New steroid compounds - Google Patents

Abstract

The invention comprises cyclpseudo-sapogenins which are isomers of iso-(22a)-sapogenins and have the following infra-red absorbtion characteristics: g max. circa 1070, 1012, 920, 895, 856 and 785 cm.-1, no absorbtion at circa 98 DEG cm.-1, said compounds being convertible to pseudo-sapogenin acetates by heating with acetic anhydride at temperatures from 100 DEG to 150 DEG C., and the preparation thereof by subjecting a pseudo-sapogenin derived from an iso-(22a)-sapogenin to the action of hydrogen to ions in the presence of an inert solvent under relatively mild conditions, i.e. conditions which are sufficient to bring about the desired isomerization but not so vigorous as to lead to the iso-(22a)-sapogenin. The isomerization may be carried out with a strong mineral acid, e.g. hydrochloric, sulphuric or phosphoric acid, or with an organic acid, e.g. acetic acid. The mineral acids are preferably used in a concentration between 0.02 and 2 per cent. Suitable inert solvents are methyl and ethyl acetate, ethanol and chloroform. Reaction temperatures may vary between 0 DEG and 50 DEG C., and in the case of hydrochloric acid, the preferred reaction temperature is 20-25 DEG C. The 3-esters of the above cyclopseudo-sapogenins containing a 3-hydroxy group may be prepared, e.g. by reaction with an acid anhydride and pyridine. The above cyclopseudo-sapogenins may be converted into pseudo-sapogenin esters by heating with a carboxylic acid anhydride, either alone or in an inert liquid medium, suitable anhydrides being aliphatic carboxylic anhydrides, e.g. acetic, propionic, butyric, valeric, caproic and capryllic anhydrides. The above cyclopseudo-sapogenins may also be converted into iso-sapogenins by the action of heat in the presence of a strong mineral acid, e.g. hydrochloric acid, preferably at a temperature between 70 DEG and 120 DEG C. In the examples the following compounds are prepared: 11-oxo-cyclopseudo-tigogenin and the 3-acetate thereof, cyclopseudo-hecogenin and the 3-acetate thereof, cyclopseudo-tigogenin, cyclopseudo-diosgenin and the 3-acetate thereof, and cyclopseudo-smilagenin and the 3-acetate thereof. The examples also exemplify the preparation of 11-oxo-psuedotigogenin diacetate from 11 - oxo - cyclopseudo - tigogenin, pseudohecogenin diacetate from cyclopseudo-hecogenin, pseudotigogenin diacetate from cyclopseudo-tigogenin, hecogenin from cyclopseudo-hecogenin, and 11-oxotigogenin from 11-oxo-cyclopseudo-tigogenin. Specifications 770,525 and 777,336 are referred to.