Methyl 2-anilinopyridine-3-carboxylate → 4-Hydroxy-1-phenyl-1,8-naphthyridin-2(1H)-one

Participants

Reaction Steps

To a stirred solution of 1 kg. of methyl 2-phenylamino-3-pyridine carboxylate in 3.97 liters of n-butyl acetate there is added portionwise, 1.1 kg. of potassium tertiary butoxide. After the addition of the potassium tertiary butoxide, there is added an additional 1.32 liters of n-butyl acetate. The reaction mixture is heated to reflux for 20 hours during which the internal temperature of the reaction mixture rose from 90° C. to 122° C. During this period, 1.8 liters of liquid is removed from the reaction mixture via a Dean-Stark trap. Xylene (3.0 liters) is added to the reaction mixture and the remainder of the n-butyl acetate is removed via the Dean-Stark trap. The reaction mixture is cooled and the potassium salt is collected by filtration, washed with toluene and air dried. The crude potassium salt is dissolved in 12 liters of water, the aqueous solution is extracted with toluene, acidified to pH 2 and the product filtered and dried; weight 937 g., m.p. 311°-313° C.

Provenance & Evidence