反应详情

6.32 g of 2-bromomethyl-5-chloroaniline hydrobromide is added to 30 ml of benzene containing 12.5% phosgene (w/v) and the mixture refluxed in a vessel equipped with a Dean-Stark trap and additional phosgene/benzene added for a total of 250 ml (over a period of 6 hrs; 1/2 ml of water collected in the trap). The reaction mixture is cooled to 20°, insolubles removed by filtration and the filtrate concentrated (solvent removed), then distilled under vacuum to obtain 2-bromomethyl-5-chlorophenylisocyanate (distills at 0.05 mm Hg/50°). Further distillation yields 2-bromomethyl 4-bromo-5-chlorophenyl isocyanate (which may be refined by crystallization from petroleum ether, m.p. 48°-50°) which is useful as an intermediate in Examples 4 and 5 in preparing 6-bromo-7-chloro-4H-1,3-benzoxazine analogs of the title product of this example.

1. temperaturethe mixture refluxed in a vessel
2. additionadded for a total of 250 ml (over a period of 6 hrs
3. custom1/2 ml of water collected in the trap)
4. temperatureThe reaction mixture is cooled to 20°
5. custominsolubles removed by filtration
6. concentrationthe filtrate concentrated
7. custom(solvent removed)
8. distillationdistilled under vacuum