Piperidine → 3-Isopropylidene-4-methoxy-1,3-dihydro-indol-2-one

Participants

Reaction Steps

A mixture of 4-methoxyoxindole (3.0 g, 18.4 mmol) and piperidine (3.5 mL, 36.89 mmol) in acetone (100 mL) is heated at reflux for 18 hours. The mixture is concentrated to dryness and triturated with methanol (20 mL). Filtration removed 800 mg of unreacted 4-methoxyoxindole. The filtrate is preadsorbed on silica gel (5 g), and purified by flash chromtography (120 g SiO2, 25% ethyl acetate:hexane to 50% ethyl acetate:hexane) to provide 700 mg (19%) of 3-isopropylidene-4-methoxy-1,3-dihydro-indol-2-one. MS (ESI+) 204.

Provenance & Evidence