Acetic Acid → Methyl-2-oxo-3-vinyl-1,2-dihydroquinoline-4-carboxylate

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Reaction Steps

To a solution of 4.4 g (20 mmol) 2-Oxo-3-vinyl-1,2-dihydroquinoline-4-carboxylic acid 4 in 200 mL methanol was added etheral diazomethane at ambient temperature until the vigorous evolution of nitrogen subsided and the starting material was used up. Then 10 mL acetic acid were added, the mixture was diluted with 200 mL diethylether and washed with a solution of sodium bicarbonate (5%) and brine. The organic layer was separated, dried over sodium sulfate and filtered. After evaporation the crude product was purified by chromatography on silica gel eluting with toluene/ethyl acetate/methanol 4:1:1, to give 2.6 g of 5 as a pale yellow solid.

Provenance & Evidence