反应详情

13.5 g of of N,N-diethyl-5-amino-2-chloro-4-fluorobenzamide in 150 ml of ethyl acetate are added dropwise while stirring within 30 minutes to a solution, heated to 70° C., of 6.7 ml of diphosgene in 50 ml of ethyl acetate. The reaction mixture is then heated at reflux temperature for 2 hours. Subsequently, the solvent is distilled off at normal pressure and the residue is distilled in a bulb-tube. There is obtained N,N-diethyl-2-chloro-4-fluoro-5-isocyanatobenzamide, b.p. 170° C./0.06 mmHg; nD 1.542, used as the starting material in Example 3.

1. temperatureThe reaction mixture is then heated
2. temperatureat reflux temperature for 2 hours
3. distillationSubsequently, the solvent is distilled off at normal pressure
4. distillationthe residue is distilled in a bulb-tube