2,5-二甲基-4-羟基-3(2H)-呋喃酮的合成研究

Synthesis of 2,5-dimethyl-4-hydroxy-3(2H)-furanone

天然产物2,5-二甲基-4-羟基-3(2H)-呋喃酮在香料工业中占有重要地位。今采用作者提出的化学反应路径选择因子对呋喃酮的合成方法进行计算比较,确定了以丙酮醛为原料,通过偶联反应合成中间体苏式3,4-二羟基-2,5-己二酮,再由成环反应制备产物呋喃酮的合成路线。考察了各个因素对偶联反应、成环反应的影响,得出较为合适的条件。并针对文献中呋喃酮分离条件苛刻、难工业化的缺点,摸索得到了较简便的呋喃酮的分离提纯方法,有利于实现呋喃酮的工业化生产。

2,5-dimethyl-4-hydroxy-3 (2H)-furanone (Furaneol) is one of the important products in the flavor industry. Using the chemical reaction route selection method proposed by the authors, a reaction route of using commercial methylglyoxal as the starting material to produce Furaneol was chosen. Through a coupling reaction of methylglyoxal to form intermediate threo-3,4-dihydroxyhexane-2,5-dione at first, the cyclization reaction was followed to form the product Furaneol. The influences of various reaction conditions on the yield were investigated, and the optimum reaction conditions are obtained as follows: (1) Coupling reaction: methylglyoxal 50g in the form of 25%(g&middotg-1) aqueous solution, glacial acetic acid 50mL diluted into 10.8%(g&middotg-1) aqueous solution, powdered zinc 36 g, reaction temperature 36-38°C, reaction time 2 h; (2) Cyclization reaction: the concentration ratio of intermediate threo-3,4-dihydroxyhexane-2,5-dione/disodium, monohydrogenphosphate and side-reaction inhibitor is 0.07 g&middotmL-1: 0.27 g&middotmL-1: 0.038 g&middotmL-1, reaction temperature 70°C, reaction time 24 h. Furthermore, a simple separation process was experimentally determined to successfully purify the Furaneol, thus benefiting the manufacture of Furaneol in industry.