Cholecalciferol

Cholecalciferol, the inactive form of vitamin D₃, is found in fish oils and is photosynthesized in human skin by sunlight. It was first prepared in the lab by A. Windaus and co-workers in 1936. Cholecalciferol undergoes two metabolic biochemical reactions that convert it to vitamin D₃’s active form, calcitriol, a hormone that mediates intestinal calcium absorption and bone calcium metabolism. Recently, T. Takahashi et al. improved the synthesis of cholecalciferol by using a flow microreactor.