Abstract
Recent progress in the thermal and photochemical isomerization of vitamin D group is reviewed. In the field of thermal isomerization, the reversible reaction between vitamin D and previtamin D and the irreversible reaction of vitamin D into pyro- and isopyrovitamin D via previtamin D are discussed. In the field of photochemical isomerization, the interconversions of provitamin D, previtamin D, lumisterol and tachysterol are discussed and then the over-irradiation products of vitamin D group are described.
