Phosgene → HCID 12478920, compound

Participants

Reaction Conditions

Reaction Steps

40 g of 50% strength aqueous sodium hydroxide solution are added to a stirred suspension of 85.8 g of 6-chloroanthranilic acid in 1,250 g of 1,2-dichloroethane in the course of 10 minutes at from 20° to 30° C. The salt suspension is freed from water by refluxing it for 1 hour in a water separator. Thereafter, 56.2 g of benzoyl chloride are added in the course of 40 minutes at from 25° to 35° C., and stirring is continued for a further 30 minutes. Under the same conditions, a further 14.1 g of benzoyl chloride are added in the course of 5 minutes, and stirring is continued for 55 minutes at 25° C. 0.2 g of dimethylformamide are added, after which 64 g of gaseous phosgene are passed into the stirred, refluxed mixture in the course of 11/2 hours, and excess phosgene is then expelled by blowing in nitrogen. The reaction mixture is cooled to 40° C., and extracted three times with water and once with a little concentrated sodium chloride solution. Evaporating down the organic phase, in the final stage at 140° C. and under 20 mbar, gives 115 g (89%) of 5-chloro-2-phenyl-4H-3,1-benzoxazin-4-one of melting point 148°-152° C. According to HPLC and comparison with an analytical standard, the purity is 86%.

Provenance & Evidence