GB730245A - Physiologically active esters of vitamin d and a method of making same - Google Patents

Abstract

The invention comprises a crystalline ester of Vitamin D3 and an aliphatic monocarboxylic acid having two to five carbon atoms in its molecule, e.g. n-butyric acid, propionic acid, isovaleric acid, said ester being antirachitically active, crystallizing in the form of colourless needles, melting at a temperature above room temperature, its ultra-violet absorption spectrum being lambda max: 265 mm , and the preparation thereof by adding an esterifying agent, e.g. a fatty acid chloride or anhydride, to a solution of Vitamin D3 in a tertiary amine, e.g. pyridine or dimethylaniline, reacting said mixture for a sufficient time to cause esterification of said Vitamin D3 and separating the resulting Vitamin D3 ester in crystalline form from the reaction mixture. The reaction mixture may be prepared in a volatile organic solvent which is removed by evaporation in vacuo before the main reaction takes place. The Vitamin D3 starting material may be resinous Vitamin D3 or crude Vitamin D3 which is obtained on irradiation of 7-dehydrocholesterol. Alternatively an ester of dehydrocholesterol is exposed to ultra-violet light to obtain the desired ester. Esterification is preferably carried out at room temperature or below. The Vitamin D3 ester is purified by recrystallization from an organic solvent.