Abstract
Tachysterol 3 is a structural isomer of vitamin D3 and is produced by exposing previtamin D3 to ultraviolet light immediately after it is generated in the skin during biosynthesis of vitamin D3 from 7-dehydrocholesterol via previtamin D3 by photochemical reaction. The instability of tachysterol3 , the conversion of tachysterol3 to its stable analogs by C14-epimerization on the CD-ring hydrindane skeleton, and the unique VDR binding mode of tachysterol3 are described in this mini-review.
