Methane → 6,7-dihydro-9-methoxy-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Diethyl ethoxymethylenemalonate (43.2 g., 0.20 mole) and 6-methoxytetrahydroquinoline (32.6 g., 0.20 mole) are mixed and heated at 125°-130° C. for three hours. Polyphosphoric acid (200 g.) is added, and the mixture is heated gradually to 220° C. then maintained at 220° C. for 1 hour. The mixture containing the product ester of Formula III is poured into about 600 ml. of water, then made basic with 40 percent sodium hydroxide solution and heated on a steam bath for 2 hours. The solution is treated with decolorizing charcoal, filtered and acidified. The solid product is isolated by filtration, washed with water and ethanol, then recrystallized from N,N-dimethylformamide to give 6,7-dihydro-9-methoxy-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid, m.p. 253°-257° C.

Provenance & Evidence