Synthesis Of Intermediate Of Yohimbine D,E Part--6-methoxyisoquinoline-5-carbonitrile

This paper belongs to one part of research of yohimbine alkaloid. Yohimbine is one of the most important complex indole alkaloid types, which occurs natrually in the bark of many rubiaceous trees. This alkaloid was first isolated from a kind of tree named yohimba in Africa, which is the name yohimbine came from. Yohimbine has extensive pharmacological properties. In ancient times the African natives, who eaten the bark of trees that contain yohimbine, regarded it as a potent aphrodisiac. Modern medicinal research revealed that yohimbine has not only notable effect on curing male erectile dysfunction, but also remarkable effect on heart disease and even on diet.Yohimbine has been isolated and characterized over a century, since then, many research work of synthesis of this complex indole alkaloid has been published. However, there was no paper about its synthesis in china. With reference to the related foreign literatures, we decided to put the synthesis of yohimbine on our schedule and design routine. Accordingto the whole designed routine, in this paper , we synthesized the intermediate --6-methoxyisoquinoline -5-carbonitrile of D, E part of yohimbine. The final product was characterized with 1'HNMR, MS and IR.We synthesized the target compounds starting with benzaldehyde, which undergoes 11 steps including nitration, reduction, Shiff base reaction, Pictet-Spengler reaction, bromination , cyanidation, dehydrogenation and so on with an overall yield 26% .This routine is reasonable and applicable for the synthesis of 6-methoxyisoquinoline-5-carbonitrile with available regents, mild condition compared to foreign published methods.