氧化铝-重铬酸钾催化氧化桦木醇合成桦木酸

Preparation of Betulinic Acid by Catalytic Oxidation of Betulin Using Alumina-potassium Dichromate as Catalyst

摘要: 利用氧化铝-重铬酸钾催化氧化桦木醇合成中间体桦木酮酸,再经选择性还原合成桦木酸。采用红外光谱(FT-IR)、氢核磁共振(1H NMR)和高效液相色谱(HPLC)对合成中间体和产物的结构变化及纯度进行了表征,并通过单因素试验,对合成工艺进行了优化研究。结果表明,合成桦木酮酸的适宜工艺条件为:K2Cr2O7与桦木醇物质的量之比为3:1,反应时间为1.5 h,反应温度为室温,Al2O3与K2Cr2O7物质的量之比为4:1。在此工艺条件下,中间体桦木酮酸的得率83.02%。经选择性还原后,目标产物桦木酸总产率为67.25%,精制后纯度为98.3%。FT-IR、 1H NMR分析确定了中间产物为桦木酮酸,产物为桦木酸。

Abstract: Betulonic acid was synthesized from betulin by catalytic oxidation using alumina-potassium dichromate as catalyst. The product was identified by FT-IR, 1H NMR and HPLC. The synthetic conditions were optimized by single-factor experiment. The results were the molar ratio of oxidizing agent to betulin 3:1, reaction time 1.5 h, room temperature, and molar ratio of catalyst to oxidizing agent 4:1. Under these conditions, the productivity of betulonic acid was 83.02%. Target compand, betulonic acid was obtained with the yield of 67.25%, and the purity of the refined betulinic acid was 98.3%.