Synthesis of[1-3H]ergosterol and [1-3H]ergocalciferol

Abstract

Two routes have been studied for the preparation from ergosta-4,22-dien-3-one of [1,2-³H₂]ergosterol. An approach via brassicasteryl acetate did not give a satisfactory yield of ergosteryl acetate after bromination and dehydrobromination in position 7, probably because of reaction in the side chain. An approach via a mixture of 3-enol acetates gave (unexpectedly)[1-³H]ergosterol in satisfactory yield. The product was converted into [1-³H]ergocalciferol.