The Separation Of Capsaicin By Low Pressure Liquid Chromatography And The Synthesis Of Piperonylic Derivative Of Capsaicin

Capsaicin has many kinds of pharmacology effect such as analgecizing, diminishing inflammation, preventing obesity, vasorelaxant, curing disease of cancer and so on. The pharmacology research of capsaicin was mainly used monomer compound. But the capsaicin with high purity is separatated by RP-HPLC or HSCCC in laboratory, in which the isolating amount is very small. Secondly, the usage of capsaicin as medecine is considerably limited because it has a strong pungency. In this paper, a method of lower pressure liquid chromatography for separation of capsaicin has been developed, and a piperonylic derivative of capsaicin (N-piperonyl-nonoylamide) without pungency was synthesized. The main contents were as follows:1. The method of lower pressure liquid chromatography for separation of capsaicin and hihydrocapsaicin from capsaicinoids was investigated in this paper. The products were separated with silica gel column chromatography at lower pressure (column:120×1cm), in which the suitable mobile phase was determined by thin layer chromatography (TLC). The separative procedure was maily as follows:The stationary phase was silica gel H, the suitable mobile phase was the mixture of petroleum ether and acetone with the ratio8:2(v/v), the flow rate was1.0mL/min, the pressure of N2was set at0.20MPa, the loading amount of capsaicinoids was3mg·(g medium)-1. The fractions deluted from the column chromatography were detected by high performance liquid chromatography (HPLC). With a circular separation (twice) of silica gel column chromatography at lower pressure, capsaicin and hihydrocapsaicin were obtained with the purity97.2%(the yield of82.2%) and96.6%(the yield of84.1%) respectively.2. A method for synthesis of N-piperonyl-nonoylamide (a piperonylic derivative of capsaicin) was developed from vanillin and pelargonic acid as raw material. The synthetic procedure was as follows:Vanillin reacted with hydrochloric acid transformed into protocatechualdehyde firstly. And the products reacted with dichloromethane to get piperonal. Then the piperonylamine was obtained from piperonal by aldoxime reaction with hydroxylamine hydrochloride and hydrogenation. Lastly, N-piperonyl-nonoylamide was synthesized from piperonal reactd with nonanoyl chloride. The influences of molar ratio of materials, the sorts of the catalyst, the kinds of organic solvent reaction time and reaction temperature on the yield of every reaction were investigated. The yield of the target product was5.1%after the purification of silica gel column chromatography. The product has no pungent odor, but a little pleasant fragrance. The structure of the target product was confirmed by means of IR,1HNMR,13CNMR and HPLC-MS.