4-甲基吡咯并[2,1,5-cd]中氮茚的合成

以2-乙基吡啶生成的叶立德为原料,采用1,3-偶极环加成反应,得到了一系列3-乙酰基(或苯甲酰基)-5-乙基中氮茚衍生物,后者与KOH在加热条件下发生分子内缩合,得到了一系列4-甲基吡咯并[2,1,5-cd]中氮茚.

Synthesis of 4-Methyl-pyrrolo[2,1,5-cd]indolizines

Pyrrolo[2,1,5-cd]indolizine is the most interesting member of bicyclo[3.2.2]azine. Its derivatives have received considerable attention in the field of synthetic organic chemistry due to their novel structure and properties,increasing biological interest and because their partially saturated frameworks occur in natural products. Over recent years the [8+2] cycloaddition of indolizine with an electron-deficient acetylene has been frequently employed for this purpose. In this paper we reported the synthesis of 5-methyl-pyrrolo[2,1,5-cd]indolizines starting from α -ethyl pyridine,which was converted at first to 3-acyl-5-ethyl indolizines by 1,3-dipolar cycloaddition of the corresponding pyridinium ylide with electron-deficient olefines and then the indolizines were transformed to pyrrolo[2,1,5-cd] indolizines by intramolecular condensation between the 3-acyl and the 5-ethyl groups.