The isomerization-cyclization of tetrahydropyridine 7 by AcOH leads to 4-ethyloctahydroindolo[2,3-a]quinolizine-2-carbaldehydes (8). When the process is carried out with aqueous AcOH, indolizidinoindole 9 is formed as a by-product in a competitive way. Compound 7 is available via reductive cyanation of pyridinium salt 1 followed by treatment of nitrile 2 with ethylmagnesium bromide.
AcOH对四氢吡啶7进行异构化-环化反应,生成4-乙基八氢吲哚并[2,3 - a ]喹啉嗪-2-甲醛(8)。当用含水AcOH进行该方法时,吲哚并吲哚并吲哚9以竞争方式形成为副产物。通过吡啶鎓盐1的还原氰化,然后用乙基溴化镁处理腈2,可获得化合物7。