Vitamin D.sub.2 analogs in which a cyclopentane ring is introduced into the side chain of 1.alpha.,25-dihydroxyvitamin D.sub.2 The compounds are characterized by a marked intestinal calcium transport activity while exhibiting much lower activity than 1.alpha.,25-dihydroxyvitamin D.sub.3 in their ability to mobilize calcium from bone. Because of their preferential calcemic activity, these compounds would be useful for the treatment of diseases where bone formation is desired, such as osteoporosis.
维生素D.sub.2的类似物中,引入了一个
环戊烷环到1.alpha.,25-二羟基
维生素D.sub.2的侧链中。这些化合物具有明显的肠道
钙转运活性,同时在从骨骼中动员
钙的能力方面比1.alpha.,25-二羟基
维生素D.sub.3表现出更低的活性。由于它们的优先
钙化活性,这些化合物将有助于治疗需要骨形成的疾病,如骨质疏松症。