Hydrochloric Acid → 4-Hydroxy-6,7-dimethoxyquinoline-3-carboxylic acid

Participants

Reaction Steps

1,4-Dihydro-6,7-dimethoxy-4-oxo-3-quinolinecarboxylic acid, ethyl ester (68.0 g, 0.245 mol) was suspended in 588 ml of 1N sodium hydroxide solution and stirred for 24 hours at 50°-60° C. To the resulting clear solution dilute hydrochloric acid was added at 0° C. The voluminous precipitate was filtered by suction and washed with water. Drying in vacuo furnished 68.2 g of the title acid, melting point 284.4° C.

Provenance & Evidence