新型凉味剂N-乙基-L-薄荷基甲酰胺的合成研究

Studies on the Synthesis of New Type Cooling Agent N-Ethyl-L-Menthyl Formamide

新型凉味剂N-乙基-L-薄荷基甲酰胺的凉感强度是薄荷醇的1.5倍,具有无气息、低挥发性、无苦味、无灼烧感、低毒性、凉感持久等优点。以L-薄荷醇为原料,通过磺酰氯酯化、氰基化反应与里特反应制备N-乙基-L-薄荷基甲酰胺。第1步薄荷磺酸酯的产率可达90%;第2步薄荷腈的产率约70%;第3步薄荷酰胺的产率约60%。采用GC-MS法将产物与标准样品进行比较,结果表明,产物为1R,3S,4S构型与1R,3R,4S构型的混合物,两者比例为67∶33。

The new cooling agent N-ethyl-L-menthyl formamide has cooling intensity 1.5 folds as strong as L- menthol. It possesses many advantages, such as weak odor, low volatility, no bitter taste, no burning sensation, low toxiticity and long-lasting cooling sensation. The synthesis of N-ethyl-L-menthyl formamide was studied by using L- menthol as starting material through esteritication with tosyl chloride, cyanation and the Ritter reaction. The yield of L- menthyl tosylate of the first step was about 90%; the second step gave menthyl cyanide in about 70% yield; N-ethyl menthyl formamide was obtained in about 70% yield. The product was compared with the authentic sample by GC/MS and the result indicated that it consisted of two isomers, and the ratio of 1R,3S,4S-isomer to 1R,3R,4S-isomer was 67/33.