一种合成α-亚甲基环酮方法的改进

An Improved Method for Synthesizing α-Methylenecycloketones

通过优化以环酮与草酸二乙酯为原料合成α 亚甲基环酮方法的反应时间、反应介质及反应温度,发现其最佳反应条件为:先以DMSO为溶剂,环酮与草酸二乙酯及氢化钠在常温下反应8h,随后在-15℃、碱性条件(pH≈9 0)下与w(HCHO)=37%的甲醛水溶液作用2h得到α 亚甲基环酮。合成了α 亚甲基环戊酮、α 亚甲基环己酮和α 亚甲基异佛乐酮。目标产物质量分数都大于95%,总收率都大于70%。

The method for synthesizing αmethylenecycloketones by condensation of cycloketones with diethyl oxalate was investigated.The optimal reaction conditions were found as follows.At first,cycloketones reacted with diethyl oxalate and sodium hydride at room temperature for 8 h in the presence of DMSO as medium.Then, the ethyloxalyl derivatives of cycloketones react with formaldehyde in basic medium(pH≈90)at -15 ℃ for 2 h to give αmethylenecycloketones.αMethylenecyclopentanone,αmethylenecyclohexanone and αmethyleneisophorone were prepared.Overall yield of two steps exceeded 70%.Purity of the products are all over 95%.