申请人:——
公开号:US20040204604A1
公开(公告)日:2004-10-14
An improved catalyst is disclosed for a process involving the preparation of benzylidene intermediates useful in the preparation of 1,4-dihydropyridine compounds and derivatives thereof useful as medicines such as for example felodipine. This is accomplished by the condensation of an aldehyde and an acetoacetate in the presence of a novel catalyst system that includes a pyridyl carboxylic acid and a secondary amine. It has been found that through the use of the present invention the purity and yield of the desired isomer of the benzylidene intermediate can be maximized, thus avoiding the requirement of additional purification steps. The use of these intermediates can then be further reacted to form the required dihydropyridines, again having a very high purity and yield compared with the prior art.
本发明公开了一种改进的催化剂,用于涉及制备苄亚甲基中间体的过程,该中间体在制备1,4-二氢吡啶化合物及其衍生物中有用,如例如非洛地平。这是通过在新型催化剂体系的存在下对醛和乙酰乙酸酯进行缩合来实现的,该催化剂体系包括吡啶基羧酸和二级胺。通过使用本发明,发现所需苄亚甲基中间体的异构体的纯度和产率可以最大化,从而避免了额外的纯化步骤的要求。然后可以进一步将这些中间体用于反应形成所需的二氢吡啶,与先前技术相比,其纯度和产率非常高。