The alkaline treatment of 1-[1-ethoxycarbonyl-2,2-bis(ethylthio)ethenyl]-2-ethylpyridinium iodide in chloroform gave the corresponding self-condensation product, 1-methyl-3-[1,1-bis(ethylthio)methylene]indolizin-2-one, in good yield, and the reaction of the indolizinone with ethyl cyanoacetate in the presence of triethylamine afforded 2-cyano-1-ethylthio-5-methyl-3-oxo-3H-pyrano[2,3-b]indolizine in
1-[1-乙氧基羰基-2,2-双(乙
硫基)
乙烯基]-2-
乙基吡啶碘化物在
氯仿中碱处理得到相应的自缩合产物1-甲基-3-[1,1-双(乙
硫基) )亚甲基]indolizin-2-one, 收率良好, 在
三乙胺存在下, indolizinone 与
氰乙酸乙酯反应得到 2-cyano-1-ethylthio-5-methyl-3-oxo-3H-pyrano[2, 3-b]
吲哚嗪,产率为 34%。