A new synthesis of 4-OR-3-penten-1-ynes (C5-fragment) as a tool for the preparation of vitamin A
作者:M. S. Brouwer、A. Hulkenberg、J. G. J. Kok、R. van Moorselaar、W. R. M. Overbeek、P. G. J. Wesselman
DOI:10.1002/recl.19790980513
日期:——
is prepared by the reaction of 1,3-dichloro-2-propanol with ethyl vinyl ether, followed by dehydrohalogenation, substitution and isomerisation of the resulting mixed acetal (17i) in a simple one-pot procedure by treatment with sodium acetylide. The syntheses of several C5-synthons of type 8 with different groups R are described. The condensation product of 1 and 8i is partially hydrogenated and subsequently
在我们的维生素A的合成技术,中间β-C 18 -酮(5)在四步序列从β紫罗兰酮(获得1)。为了减少反应步骤的数目,1被冷凝与C 5 -Fragment,导致的汇集合成5。R = -CH(OC 2 H 5)-CH 3(8i)的标题化合物(8)是通过1,3-二氯-2-丙醇与乙基乙烯基醚反应,然后进行脱卤化氢,取代和异构化而制备的。所得的混合乙缩醛(17i)通过乙炔钠处理,以简单的一锅法进行。描述了具有不同基团R的8型的几个C 5-合成子的合成。1和8i的缩合产物被部分氢化,然后水解为5,总产率为85%。