甲基酮香料的仿生合成新方法研究

四氢叶酸辅酶在生物体内的作用是转移不同氧化态的一碳单元, 当一碳单元处于甲酸氧化态时, 活性部位是具有五元环状结构的咪唑啉环. 模拟四氢叶酸辅酶转移一碳单元的反应, 以苯并咪唑甲基碘盐作为四氢叶酸辅酶甲酸氧化态模型, 以格利雅试剂甲基碘化镁作为接收一碳单元的亲核试剂, 将甲酸氧化态的一碳单元转移给甲基碘化镁, 成功合成了三种重要的甲基酮香料甲基己基酮、甲基壬基酮和甲基十一烷基酮, 其结构用元素分析, 1H NMR, IR和MS等方法进行了表征, 并对反应机理和反应条件进行了讨论, 为甲基酮香料提供了一种仿生合成新方法.

A Novel Method for Biomimetic Synthesis of Methyl Ketone Perfume

The tetrahydrofolate coenzymes are involved in the biochemical transfer of a one-carbon fragment at different oxidation levels.When the one-carbon unit is at the formic oxidation level,the imidazoline with a five-membered ring structure is the active site.In this paper,three benzimidazolium salts were respectively used as a tetrahydrofolate coenzyme model at formic acid oxidation level and methyl magnesium iodide as a nucleophile to which one-carbon unit was transferred.Thus the biomimetic synthesis of three important methyl ketone perfumes,methyl hexyl ketone,methyl nonyl ketone,and methyl undecyl ketone was successfully accomplished by using the addition-hydrolysis reaction of the corresponding benzimidazolium salts with methyl magnesium iodide.Their structures were characterized by elemental analysis,1H NMR,IR and MS techniques.The reaction mechanism and the effects of reaction conditions on the yield were investigated.A novel convenient method for biomimetic synthesis of methyl ketone perfumes from carboxylic acids has been thus provided.