Trifluoroacetic acid → HCID 46914013, compound

Participants

Reaction Conditions

Reaction Steps

To a trifluoroacetic acid solution (47 mL) containing 3-(3-ethoxy-3-oxopropyl)-4-oxo-4,5,6,7-tetrahydro-1H-indole (4, 10.0 g, 42.5 mmol) was added with trimethylorthoformate (13.6 g, 128 mmol) at 0° C. The reaction was stirred at 0° C. for 30 min, warmed up to room temperature and stirred for 2.0 h. The solution was added with ethyl acetate (250 mL), water (200 mL) and NaOH (18 g). The organic layer was collected and washed with saturated aqueous NaHCO3 (200 mL), dried over MgSO4 (s), and concentrated under reduced pressure. The oily residue was purified by gravity column chromatography (50% EtOAc in hexanes) to give 3-(3-ethoxy-3-oxopropyl)-2-formyl-4-oxo-4,5,6,7-tetrahydro-1H-indole (5, 2.1 g, 8.0 mmol) as yellow solids in 19% yield.

Provenance & Evidence