Process for obtaining '25-hydroxyketone Windaus' comprising the Wittig-Horner reaction.

摘要

Vitamin D2 or ergocalciferol, is an analogue of vitamin D. Vitamin D3 difference by the presence of a trans double bond and an extra methyl group in the side chain. The present invention describes a method of obtaining 25-hydroxyketone Windaus-Grundmann (22E, 24S) -de-A, B-25-Hidroxiergost-22-en-8-one, precursor of a large number of analogues vitamin D2, an applying route Wittig-Horner reaction to generate the trans double bond and used as starting compound of Inhoffen-Lythgoe diol readily available from commercial vitamin D2.