用Wittig和Wittig-Horner反应合成藏红花酸二甲酯

以短碳链化合物1,4-二溴-2-丁烯、丙酮醛缩二甲醇、2-溴丙酸甲酯和氯乙醛为起始原料,首先分别合成2,7-二甲基-2,4,6-辛三烯-1,8-二醛和γ-氯代惕各酸甲酯,然后将两者结合而成藏红花酸二甲酯。合成过程中碳碳双键的形成为关键步骤。通过比较Wittig和Wittig-Horner反应在双键形成中的作用,得出结论:合成2,7-二甲基-2,4,6-辛三烯-1,8-二醛时,宜用Wittig-Horner反应,产率为58.7%;合成γ-氯代惕各酸甲酯和藏红花酸二甲酯时,宜用Wittig反应,产率分别为74.3%和78.6%。

Synthesis of Crocetin Dimethyl Ester with Wittig and Wittig-Horner Reaction

The short carbon-chain compounds,such as 1,4-dibromo-2-butene,dimethoxyacetone,2-bromo methyl propionate and chloroacetaldehyde,were used as raw materials to prepare 2,7-dimethyl-2,4,6-octatriene-1,8-dial and γ-chloro methyl tiglate respectively.Then crocetin dimethyl ester was synthesized from the two intermediates.Wittig and Wittig-Horner reaction were applied in the key steps of the construction of carbon carbon double bonds.The results showed that 2,7-dimethyl-2,4,6-octatriene-1,8-dial could be obtained by Wittig-Horner reaction with the yield of 58.7%,while γ-chloro methyl tiglate and crocetin dimethyl ester could be obtained by Wittig reaction with the yield respectively of 74.3% and 78.6%.