24,24-Difluoro-26,27-dimethylvitamin D.sub.3 derivatives represented by formula: ##STR1## wherein X represents a hydrogen atom or a hydroxyl group. These compounds are prepared by irradiating 24,24-difluoro-26,27-dimethylcholesta-5,7-diene-(1.alpha.,)3.beta., 25-di- or triol with ultraviolet light, and is useful for the prevention or treatment of, for example, calcium pathobolism or osteoporosis.
24,24-二
氟-26,27-二甲基
维生素D.sub.3衍
生物的
化学式为:##STR1## 其中X代表氢原子或羟基。这些化合物通过紫外线辐射24,24-二
氟-26,27-二甲基胆甾-5,7-二烯-(1α,)3β,25
-二醇或三醇制备而成,可用于预防或治疗
钙代谢异常或骨质疏松症等疾病。