Process for the preparation of novel pregnane derivatives

摘要

Novel pregnane derivatives which can be used for the preparation of cholecalciferol derivatives and of the formula <IMAGE> in which R<20> denotes hydroxymethyl or easily cleavable etherified hydroxymethyl, are prepared starting from pregna-1,4,6-trien-3-one derivatives via 1 alpha ,2 alpha -epoxypregna-4,6-dien-3-one derivatives. In the compounds of the formula I obtained, the hydroxyl groups in the 1- and 3-position can be etherified or esterified to give etherified or esterified hydroxyl groups which are easily cleavable to the hydroxyl group. The hydroxymethyl group in the 20-position of a compound of the formula I can be oxidised to a formyl or carboxyl group.