申请人:Teijin Limited
公开号:US04388243A1
公开(公告)日:1983-06-14
The present invention relates to a novel process for the preparation of active-type vitamin D.sub.3 compounds and their intermediates. In accordance with the present invention, a large amount of an active-type vitamin D.sub.3 compounds, for example 1.alpha.-hydroxycholecalciferol, 1.alpha.,25-dihydroxycholecalciferol and the like, is efficiently prepared with high industrial advantages by a novel processes, which comprises (i) reacting hydroxycholesta-5-enes having the hydroxyl groups protected with lower alkoxycarbonyl group as a starting material with allylic brominating agent and dehydrobrominating agent to prepare the corresponding hydroxycholesta-5,7-dienes, (ii) exposing the hydroxycholesta-5,7-dienes to ultraviolet irradiation or to a combination of the irradiation with thermal isomerization to obtain a mixture of the unreacted hydroxycholesta-5,7-dienes and previtamin D.sub.3 compounds or a mixture of the unreacted hydroxycholesta-5,7-dienes and the protected active-type vitamin D.sub.3 compounds, (iii) separating the mixture into the unreacted hydroxycholesta-5,7-dienes and previtamin D.sub.3 compounds or the protected active-type vitamin D.sub.3 compounds, (iv) recycling the unreacted hydroxycholesta-5,7-dienes as reuse and (v) thermally isomerizing the remaining compounds and/or splitting off the protective groups. The process for the preparation of active-type vitamin D.sub.3 compounds, in the present invention, is of very high industrial value, capable of carrying out by simple operation and adaptable to large scale commercial production.
本发明涉及一种新型过程,用于制备活性型维生素D.sub.3化合物及其中间体。根据本发明,通过一种新型工艺高效地制备大量活性型维生素D.sub.3化合物,例如1α-羟基胆钙化醇、1α,25-二羟基胆钙化醇等,具有高工业优势,该工艺包括:(i) 以羟基胆固醇-5-烯作为起始原料,其羟基团被低碳酰基团保护,与烯丙基溴化剂和去溴化剂反应,制备相应的羟基胆固醇-5,7-二烯,(ii) 将羟基胆固醇-5,7-二烯暴露于紫外辐射或紫外辐射与热异构化的组合作用下,获得未反应的羟基胆固醇-5,7-二烯和前维生素D.sub.3化合物的混合物或未反应的羟基胆固醇-5,7-二烯与保护的活性型维生素D.sub.3化合物的混合物,(iii) 将混合物分离为未反应的羟基胆固醇-5,7-二烯和前维生素D.sub.3化合物或保护的活性型维生素D.sub.3化合物,(iv) 回收未反应的羟基胆固醇-5,7-二烯以进行再利用,(v) 对剩余化合物进行热异构化和/或去除保护基。本发明中用于制备活性型维生素D.sub.3化合物的工艺具有非常高的工业价值,能够通过简单操作进行,并适用于大规模商业生产。