Diethyl Malonate → 6-Nitro-2-oxo-1,2-dihydro-quinoline-3-carboxylic acid ethyl ester

Participants

Reaction Steps

A solution of 10.0 g (46 mmol) of 1,2-dihydro-2-oxo-3-quinolinecarboxylic acid, ethyl ester [J. Chem. Soc., 2518 (1962)] and 50 ml of sulfuric acid is stirred in an ice bath and a cold mixture of 9.75 ml of 70% nitric acid and 9.75 ml of sulfuric acid is added dropwise over 10 minutes. The reaction solution is stirred with ice bath cooling for 1 hour and then is poured into ice and water with stirring. The resulting solid is collected by filtration and washed with water and ethanol. After drying, 10.7 g of the requisite ester is obtained, mp>310°. The structure is assigned by an unequivocal synthesis from the condensation of 2-amino-5-nitrobenzaldehyde and diethyl malonate to give the same 1,2-dihydro-6-nitro-2-oxo-3-quinolinecarboxylic acid, ethyl ester.

Provenance & Evidence