| abstract |
PROBLEM TO BE SOLVED: To establish a method for stably supplying a high-purity purified product of a vitamin D derivative, particularly ED-71, in a large amount. According to the present invention, there is provided a compound represented by the formula (I): Crystals of a compound represented by the following formula: Crystals of a vitamin D derivative obtained by purifying an unpurified or crudely purified vitamin D derivative by reversed-phase chromatography, and then crystallizing the same with an organic solvent; A novel by-product formed therein; and a method for purifying a vitamin D derivative or a precursor thereof are provided. |