反应详情

温度

90 °C

A solution of 2,4-dichlorophenyl isocyanate (18.8 g, 0.10 mol) in acetone (50 ml) is metered at room temperature into a solution of ethyl 5-fluoroanthranilate (18.3 g, 0.10 mol) in acetone (70 ml). After addition is complete the mixture is stirred at 90° C. for 2.5 hours. 1.80 ml of a 30% strength solution of methanolic sodium methoxide (0.010 mol) are metered in and the mixture is stirred under reflux for a further 2 hours. After cooling, the product is filtered off with suction and washed with 3×15 ml of acetone. The acetone-moist precipitate is treated with dilute hydrochloric acid and the residual acetone is removed by azeotropic distillation. The product is then filtered off with suction, washed with water and dried. 31.7 g of 3-(2,4-dichlorophenyl)-6-fluoro-2,4(1H,3H)-quinazolinedione (yield: 97.5% of theory) of melting point 313° to 314° C. are obtained.

1. additionAfter addition
2. stirringis stirred
3. temperatureunder reflux for a further 2 hours
4. temperatureAfter cooling
5. filtrationthe product is filtered off with suction
6. washwashed with 3×15 ml of acetone
7. additionThe acetone-moist precipitate is treated with dilute hydrochloric acid
8. customthe residual acetone is removed by azeotropic distillation
9. filtrationThe product is then filtered off with suction
10. washwashed with water
11. customdried