5-[2-(乙硫基)丙基]-1,3-环己二酮的合成工艺研究

研究优化了合成烯草酮、烯禾定以及cloproxydim等环己烯酮类除草剂的重要中间体5-2-(乙硫基)丙基]-1,3-环己二酮的合成方法.首先,巴豆醛与乙硫醇在三乙胺中高收率制得3-乙硫基丁醛,然后以乙酰乙酸甲酯为原料,通过碱水解、与3-乙硫基丁醛缩和、脱水三步反应合成6-乙硫基庚烷-3-烯-2-酮,接着6-乙硫基庚烷-3-烯-2-酮与丙二酸二甲酯经Michael加成和Claisen缩合,再通过皂化和脱羧反应生成目标化合物5-2-(乙硫基)丙基]-1,3-环己二酮,主要中间产物以及目标产品均与标准品对照,经液质联用确认.

Synthesis of 5-[2-(ethylthio)propyl]-1,3-cyclohexanedione

5-2-(ethylthio)propyl]-1,3-cyclohexanedione, the title compound of this study, is an important intermediate for preparation of 3-hydroxy-cyclohex-2-enones herbicides, such as clethodim, sethoxydim, cloproxydim, etc.. The optimization of the synthesis route and the preparation method of the title compound were studied and the results were described concisely as follows. Firstly, 3-ethylthiobutanal was prepared with high yield by reacting crotonaldehyde with ethanethiol in triethylamine. Secondly, methyl acetoacetate was converted to 6-ethylthiohept-3-en-2-one via three steps, hydrolysis, condensation with 3-ethylthiobutanal and dehydration, then the 6-ethylthiohept-3-en-2-one was cyclocondensed with di-Me malonate by Michael addition and Clasisen condensation, and further via saponification and decarboxylation , the title compound was obtained. The products of each steps and the final title compound obtained were compared with each its own standerd samples and were confirmed by LC/MS.