Chloroform → 2,7-Dichloro-6-fluoro-3-formyl-1,4-dihydroquinoline

Participants

Reaction Conditions

Reaction Steps

Phosphoryl chloride (55.6 cc) is added in the course of 30 minutes, with stirring at between 10° and 15° C. to a mixture of trichloromethane (250 cc) and dimethylformamide (54 cc) and the mixture is stirred for 1 hour at a temperature in the region of 20° C. To the solution obtained, 7-chloro-6-fluoro-3,4-dihydrocarbostyril (52 g) is added gradually in the course of 10 minutes at approximately 20° C. with vigorous stirring. The suspension obtained is heated to a temperature in the region of 60° C. and kept stirring for a further 2 hours at this temperature. The reaction mixture is concentrated under reduced pressure (20 kPa) at 50° C. until a pasty mixture is obtained. A mixture of water (250 cc) and crushed ice (250 g) is added with vigorous stirring. The solid obtained is drained at approximately 5° C. and washed with water (4×125 cc) at 5° C. The wet product obtained and sodium acetate (58 g) are added simultaneously in the course of 1 hour to water (500 cc) at 90° C., so as to maintain the pH at approximately 6. The mixture is stirred for a further 15 minutes at 90° C., the temperature is allowed to fall to approximately 50° C. and the product is drained at this temperature and washed with water (3×250 cc) at approximately 20° C. 2,7-Dichloro-6-fluoro-3-formyl1,4-dihydroquinoline (54.3 g) is obtained in the form of a yellow solid, m.p. 260° C., which is used without further treatment for the subsequent steps.

Provenance & Evidence