Sulfuric Acid → 6,7-Dimethoxy-4-(3,4-dimethoxyphenyl)-3-ethoxycarbonylquinoline-2-acetic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a mixture of 2-amino-4,5,3',4'-tetramethoxybenzophenone (50.0 g), acetonedicarboxylic acid diethyl ester (35.0 g) and acetic acid (400 ml), concentrated sulfuric acid (1.5 ml) was added, followed by stirring at 100° C. for 2.5 hours. The reaction mixture was concentrated under reduced pressure, and the residue was poured over water, neutralized with a saturated aqueous sodium hydrogen carbonate solution and then extracted with chloroform. The chloroform layer was washed with water and dried (MgSO4), after which the solvent was distilled off under reduced pressure. The residual crystal was recrystallized from ethanol to yield 6,7-dimethoxy-4-(3,4-dimethoxyphenyl)- 3-ethoxycarbonylquinoline-2-acetic acid ethyl ester (55.6 g, 73%) as a colorless prismatic crystal having a melting point of 146° to 147° C.

Provenance & Evidence