Ethanol → Vitamin D4

Participants

Reaction Steps

22,23-dihydroergosterol (VIII) (2.0 g., 5.0 mmol.) was dissolved in a solution of diethyl ether and benzene (4:1, 600 ml.) and irradiated (Hannovia immersion lamp 450 watts) with stirring under argon in a water cooled quartz vessel for three hours. The solution was concentrated in vacuo to yield a gummy liquid, redissolved in 100 ml. of ethanol and heated at reflux under argon for eight hours. Then, the solution was concentrated in vacuo and the residue was adsorbed on a silica gel column and eluted with 30% ethyl acetate in hexane to afford Vitamin D4 (22,23-dihydroergocalciferol) (IX). 1.2 g. (60%). 1H NMR: (400 MHz, CDCl3), δppm 0.55 (3H, s, 18-H3) 0.78 (6H, dd, 26-H3 and 27-H3) 0.87 (3H, d, 21-H3) 0.93 (3H, d, 28-H3) 3.94 (1H, m, 3-H) 4.82 (1H, m (sharp), 19-H), 5.04 (1H, m (sharp), 19-H), 6.04 (1H, d, 7-H) 6.24 (1H, d, 6-H).

Provenance & Evidence