Hydrochloric Acid → 5,8-Difluoroquinolin-2(1H)-one

Participants

Reaction Steps

10 g of 2,5-difluoroaniline and 6 g of pyridine in 350 ml of dichloromethane are mixed drop by drop at 0° C. with 12.9 g of cinnamic acid chloride and stirred until conversion is completed at 0° C. The batch is added to 2N hydrochloric acid, and it is extracted with dichloromethane. It is washed with water, dried with sodium sulfate and concentrated by evaporation in a vacuum. The solid that is obtained is mixed with 11.1 g of aluminum chloride and heated for 8 hours to 150° C. After chromatography on silica gel, 2.9 g of 5,8-difluoroquinolin-2(1H)-one is obtained. The latter is reacted in 100 ml of ethylene glycol in the presence of 780 mg of copper(II) oxide for 20 hours at 200° C. in ammonia atmosphere at 60 bar. After chromatography on silica gel, in this case 5-amino-8-fluoroquinolin-2(1H)-one is obtained as fraction A and 2,5-diamino-8-fluoroquinoline is obtained as fraction B.

Provenance & Evidence