A synthesis of 25‐hydroxycholecalciferol‐(26, 27‐3H)

Abstract
The synthesis of 25‐hydroxycholecaleiferol‐(26, 27‐3H) is described. 25‐Oxo‐27‐norcholesta‐5, dien‐3β‐yl acetate is converted photochemically to 25‐oxo‐27‐norcholecalciferol‐3‐acetate, which is then reacted with tritiated methylmagnesium iodide and subsequently saponified to give 25‐hydroxycholecalciferol‐(26, 27‐3H).