26138-64-7

81937-41-9

26138-64-7

General procedure for the synthesis of 3-acetyl-4-hydroxyquinolin-2(1H)-one from methyl 2-(acetoacetylamino)benzoate: 0.43 g (18.8 mmol) of sodium metal and 30 mL of anhydrous methanol were added to a 100 mL round-bottomed flask, and the mixture was stirred until the sodium metal was completely dissolved. Subsequently, 20 mL of anhydrous dichloromethane was added, stirred well, then 4.43 g (18.8 mmol) of methyl 2-(acetoacetylamino)benzoate was added to ensure homogeneous mixing. The reaction mixture was heated to reflux for 5 hours and then cooled to room temperature. 50 mL of ice water was added to the reaction mixture and the pH was adjusted to strongly acidic with dilute hydrochloric acid, at which point a large amount of white solid precipitated. The white solid was collected by filtration, washed sequentially with water and ethanol, and dried to give 3.66 g of the white solid product 3-acetyl-4-hydroxyquinolin-2(1H)-one with a melting point of 256-257 °C and a yield of 95.7%.