申请人:Hoechst-Roussel Pharmaceuticals Inc.
公开号:US04734513A1
公开(公告)日:1988-03-29
A method of regioselectively and stereoselectively synthesizing forskolin (8,13-epoxy-1.alpha.,6.beta.,7.beta.,9.alpha.-tetrahydroxylabd-14-en-11-on e) from 9-deoxyforskolin (8,13-epoxy-1.alpha.,6.beta.,7.beta.-trihydroxylabd-14-en-11-one) with a good yield is described. In a preferred embodiment, it comprises an enol ether formation from 8,13-epoxy-1.alpha.,6.beta.,7.beta.-trihydroxylabd-14-en-11-one-6,7-carbon ate, oxidation of the enol ether with a suitable peroxy acid to obtain 11,12-dehydro-8,13-epoxy-11-methoxy-1.alpha.,6.beta.,7.beta.,9.beta.-tetra hydrolabd-14-ene-6,7-carbonate and hydrolysis of the latter under an acidic condition to obtain 8,13-epoxy-1.alpha.,6.beta.,7.beta.,9.alpha.-tetrahydroxylabd-14-en-11-one -6,7-carbonate. As an alternative way of protecting the two hydroxy groups at carbon-6 and carbon-7, they may also be converted to dimethyl acetal during the synthetic sequence. Four compounds produced in the synthetic scheme as intermediates, namely, 9,11-dehydro-8,13-epoxy-11-methoxy-1.alpha.,6.beta.,7.beta.-trihydroxylabd -14-ene-6,7-carbonate and 11,12-dehydro-8,13-epoxy-11-methoxy-1.alpha.,6.beta.,7.beta.,9.alpha.-tetr ahydroxylabd-14-ene-6,7-carbonate and the corresponding dimethyl acetal compounds are believed to be novel.
本文介绍了一种从9-去氧福斯科林(8,13-环氧-1.alpha.,6.beta.,7.beta.,9.alpha.-四羟基拉布-14-烯-11-酮)高产地选择性和立体选择性合成福斯科林(8,13-环氧-1.alpha.,6.beta.,7.beta.,9.alpha.-四羟基拉布-14-烯-11-酮)的方法。在优选实施例中,该方法包括从8,13-环氧-1.alpha.,6.beta.,7.beta.-三羟基拉布-14-烯-11-酮-6,7-碳酸酯形成烯醚,用适当的过氧酸氧化烯醚以获得11,12-去氢-8,13-环氧-11-甲氧基-1.alpha.,6.beta.,7.beta.,9.beta.-四羟基拉布-14-烯-6,7-碳酸酯,并在酸性条件下水解后得到8,13-环氧-1.alpha.,6.beta.,7.beta.,9.alpha.-四羟基拉布-14-烯-11-酮-6,7-碳酸酯。作为保护碳-6和碳-7处两个羟基的另一种选择,它们也可以在合成序列中转化为二甲基缩醛。本合成方案中产生的四个中间体化合物,即9,11-去氢-8,13-环氧-11-甲氧基-1.alpha.,6.beta.,7.beta.-三羟基拉布-14-烯-6,7-碳酸酯和11,12-去氢-8,13-环氧-11-甲氧基-1.alpha.,6.beta.,7.beta.,9.alpha.-四羟基拉布-14-烯-6,7-碳酸酯及相应的二甲基缩醛化合物被认为是新颖的。