(E)-2-chloro-3-(hydroxymethylene)cyclohex-1-ene-1-carbaldehyde 、
1-(2-carboxyethyl)-2,3,3-trimethyl-3H-indol-1-ium 在
sodium acetate 、
乙酸酐 作用下,
以33 %的产率得到3-[2-[2-[3-[2-[1-(2-Carboxyethyl)-3,3-dimethylindol-1-ium-2-yl]ethenyl]-2-chlorocyclohex-2-en-1-ylidene]ethylidene]-3,3-dimethylindol-1-yl]propanoic acid