The present invention describes a novel synthetic method for preparing the key intermediate 2,6,10-trimethyl-1,1-dialkoxy-3,5,9-undecatriene of lycopene. An existing synthetic method have some disadvantages that it is very difficult to gain the raw material dialkyl 4-methyl-5,5-diakoxy-1-pentene-1-phosphonate (10) because no effective synthetic method can be adopted, and furthermore the obtained target compound is composed of several cis/trans isomers. This invention relates to a process comprising a condensation step wherein a starting C10-phosphonate is changed to its carbanion completely at a temperature of −40˜30 under an atmosphere of a non-reactive gas in an organic solvent catalyzed by base, and then C4-dialkyl is added to undergo Wittig-Horner condensation. This invention affords all trans C14-acetal and this method is characterized with the advantages of simple procedure, easy access to raw material and low cost, which makes it has the value of industrial application.
本发明描述了一种新颖的合成方法,用于制备
番茄红素的关键中间体2,6,10-三甲基-1,1-二烷氧基-3,5,9-十一烯。现有的合成方法存在一些缺点,即很难获得原料二烷氧基-4-甲基-5,5-二烷氧基-1-
戊烯-1-
膦酸酯(10),因为没有有效的合成方法可采用,而且所得目标化合物由几种顄/反异构体组成。本发明涉及一种包括缩合步骤的过程,在该过程中,起始的C10-
膦酸酯在非反应性气体氛围下,在有机溶剂中由碱催化完全变为其碳负离子,然后加入C4-二烷基进行威蒂-霍纳缩合。本发明提供了全顄C14-
缩醛,该方法具有简单的操作程序、易获得原料和低成本的优点,使其具有工业应用的价值。