反应详情

Dimethyl 2-methoxycarbonyl-6-nitrophenylmalonate (3.0 g) was refluxed in 50 mL of 6 N hydrochloric acid overnight. The mixture was concentrated to dryness and refluxed for 2 hours with 1.1 g of tin(II) chloride in 20 mL of ethanol. The mixture was filtered through Celite, concentrated and chromatographed on silica gel (ethyl acetate:hexane:acetic acid) to give 0.65 g (37% yield) of 4-carboxy-2-oxindole as a white solid.

1. concentrationThe mixture was concentrated to dryness
2. temperaturerefluxed for 2 hours with 1.1 g of tin(II) chloride in 20 mL of ethanol
3. filtrationThe mixture was filtered through Celite
4. concentrationconcentrated
5. customchromatographed on silica gel (ethyl acetate:hexane:acetic acid)