反应详情

温度

15 °C

To a suspension of 3-(3,5-dichlorophenyl)-ureidoacetic acid (813 g.) in chlorobenzene (3,500 cc.) is added concentrated sulphuric acid (d = 1.83) (16 cc.), representing 0.095 mol per mol of ureidoacetic acid. The water formed in the reaction is removed by azeotropic distillation. After 45 minutes' distillation, a limpid solution is obtained. After cooling to about 15° C, the precipitate formed is filtered off and washed on the filter with ethanol (500 cc.) at 10° C. After drying, 3-(3,5-dichlorophenyl)-hydantoin (724 g.) melting at 199° C is obtained. Yield: 95.4%.

1. customis removed by azeotropic distillation
2. distillationAfter 45 minutes' distillation
3. customa limpid solution is obtained
4. customthe precipitate formed
5. filtrationis filtered off
6. washwashed on the
7. filtrationfilter with ethanol (500 cc.) at 10° C
8. customAfter drying