Autoxidation of isotachysterol

Isotachysterol, the acid-catalyzed isomerization product of vitamin D3, produces seven previously unknown oxygenation products in a self-initiated autoxidation reaction under atmospheric oxygen in the dark at ambient temperature. They are (5R)-5,10-epoxy-9,10-secocholesta-6,8(14)-dien-3β-ol (), (5S)-5,10-epoxy-9,10-secocholesta-6,8(14)-dien-3β-ol (), (10R)-9,10-secocholesta-5,7,14-trien-3β,10-diol (), (10S)-9,10-secocholesta-5,7,14-trien-3β,10-diol (), (7R,10R)-7,10-epoxy-9,10-secocholesta-5,8(14)-dien-3β-ol (), 5,10-epidioxyisotachysterol () and 3,10-epoxy-5-oxo-5,10-seco-9,10-secocholesta-6,8(14)-dien-10-ol (). The formation of these products is explained in terms of free radical peroxidation chemistry.