以假性紫罗兰酮为原料合成紫罗兰酮

Synthesis of Violet Ketone with Pseudoviolet Ketone

紫罗兰酮是一种商业价值较高的香料,具有木香型香气,按照双键位置的不同,分别有3种异构体:α-紫罗兰酮,β-紫罗兰酮,γ-紫罗兰酮,其中β-紫罗兰酮异构体是重要的医药中间体。本课题以假性紫罗兰酮为原料,通过环化剂环化合成了紫罗兰酮。气相色谱的分析结果表明所得目标化合物与标样一致。在0.266kPa压力下,分别收集121~122℃(α-紫罗兰酮的沸程)和127~128℃(β-紫罗兰酮的沸程)馏段的馏分,均为淡黄色液体。实验结果表明,合成过程中的最佳环化剂是浓磷酸,最佳溶剂是三氯甲烷,最佳时间是2h,最佳反应温度是0℃,环化剂浓磷酸与原料假性紫罗兰酮的最佳体积比是4∶1,溶剂三氯甲烷与原料假性紫罗兰酮的最佳体积比为1∶1。在此最佳条件下,采用减压蒸馏的方法提纯,得到的总酮产率为97.8%(其中α-紫罗兰酮的产率为70.6%,β-紫罗兰酮的产率为27.2%)。

Ionone was a kind of wood-type aroma of valuable spices.According to the location of double bond,ionone had three isomers:α-ionone,β-ionone andγ-ionone.β-ionone isomer was an important pharmaceutical intermediates.In this paper,false ionone was applied as raw materials to synthesis ionone by cyclization.Gas chromatography results showed that the target compounds were consistent with the standard samples.Under the pressure of 0.266kPa,the fractions of 121~122℃(boiling range ofα-ionone)and 127~128℃(boiling range ofβ-ionone)were collected respectively,which were light yellow liquid.Experiment proved that the best activator was phosphoric acid,the best solvent was chloroform,the best time was 2h,the best reaction temperature was 0℃,the best-volume ratio of phosphoric acid to false ionone was 4:1,the best volume ratio of chloroform to false ionone was 1:1.Under these best conditions,by the vacuum distillation method of purification,the total yield was 97.8%(α-ionone was 70.6%,β-ionone was 27.2%).