GB467376A - Process for the manufacture of unsaturated neutral oxidation products of stigmasterol compounds - Google Patents

Abstract

Unsaturated neutral oxidation products of stigmasterol which still contain the cyclopentanopolyhydrophenanthrene nucleus and the full side chain are prepared by the oxidation of esters of stigmasterol without intermediate protection of the double bond with oxidizing agents under mild conditions, followed by the separation from the oxidation product of the neutral fraction. Suitable mild oxidation conditions are obtained by the use of a dilute solution of chromic acid or potassium permanganate in glacial acetic acid at room temperature. The oxidation conditions are further illustrated by reference to literature. The products of the invention comprise neutral bodies which possess the nucleus and side chain of stigmasterol together with other oxygen containing groups, which may be keto groups. The bodies which contain keto groups are separated from those which do not, by the usual ketone reage ts such as semicarbazide &c. An alternative method for the separation of the neutral oxidation products is fractional crystallization. In an example a glacial acetic acid solution of stigmasterol acetate is treated with a dilute glacial acetic solution of chromic acid and allowed to remain at room temperature for 3 days. The product is diluted with water and extracted with ether. The ethereal solution is extracted with alkali to remove the acid portion and the neutral portion which remains is isolated and fractionally crystallized. The less soluble portion consists mainly of a hydroxy ketone which is purified by ketone reagents, while the more soluble portion consists mainly of a compound containing no keto group and having the empirical formula C31H50O5.