GB731701A - Steroid enol esters - Google Patents

Abstract

The invention comprises 3 : 20-dienol acylates and 3 : 11 : 20-trienol acylates of pregnane-3 : 11 : 20-trione, having the formulae: <FORM:0731701/IV (b)/1> and <FORM:0731701/IV (b)/2> respectively (wherein the acyl group (Ac) is derived from an organic carboxylic acid, preferably containing from 1-8 carbon atoms, and which may further contain, as non-reactive substituents, halogen atoms or alkyl or alkoxy groups, e.g. acetyl, propionyl, octanoyl, phenylacetyl, benzoyl, chloroacetyl, and methoxybenzoyl), and the preparation thereof by heating pregnane-3 : 11 : 20-trione with an organic carboxylic anhydride in the presence of an acid catalyst (e.g. p-toluenesulphonic acid, sulphosalicylic acid or sulphuric acid). The anhydride is preferably present in excess, and when preparing 3 : 20-dienol acylates the progress of the reaction is followed by titration of the distillate. Inert solvents may be used, particularly toluene. In examples (1) pregnane-3 : 11 : 20-trione, acetic anhydride and p-toluene sulphonic acid are refluxed so that the anhydride slowly distils, and the residue after chromatography yields the 3 : 11 : 20 - trienol acetate; (2) pregnane-3 : 11 : 20-trione, sulphosalicylic acid, acetic anhydride and toluene are distilled until distillate contains two equivalents of acetic acid, when residue yields the 3 : 20-dienol acetate. Other examples describe the preparation of the 3 : 20-di-enol propionate and octanoylate; and the 3 : 11 : 20-tri-enol propionate and butyrate.