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

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。

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%.