A practical synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene, the key intermediate of Ivabradine, was developed in four or five steps using two different routes. 2-Bromo-4,5-dimethoxyhydrocinnamonitrile was produced via the condensation of 2-bromo-4,5-dimethoxybenzaldehyde with acetonitrile or cyanoacetic acid and reduction by NaBH4. Cyclisation gave 1-cyano-4,5-dimethoxybenzocyclobutene. Overall yields of the routes A and B were 30% and 37% respectively. Route B is a short and simple route, permitting the synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene on a large scale.
伊伐布雷定的关键中间体--1-氰基-4,5-二甲氧基苯并环丁烯的实用合成方法采用两种不同的路线,分四到五个步骤进行。通过 2-溴-4,5-二甲氧基苯甲醛与乙腈或氰乙酸缩合,并用 NaBH4 还原,制得 2-溴-4,5-二甲氧基氢化肉桂腈。环化后得到 1-氰基-4,5-二甲氧基苯并环丁烯。路线 A 和 B 的总产率分别为 30% 和 37%。路线 B 是一条简捷的路线,可以大规模合成 1-氰基-4,5-二甲氧基苯并环丁烯。