[Br:1][C:2]1[CH:9]=[CH:8][C:5]([CH2:6][NH2:7])=[C:4]([F:10])[CH:3]=1.Cl.Cl.BrC1C=CC(CN)=C(F)C=1.[C:23](Cl)(Cl)=[O:24]>C1(C)C=CC=CC=1>[Br:1][C:2]1[CH:9]=[CH:8][C:5]([CH2:6][N:7]=[C:23]=[O:24])=[C:4]([F:10])[CH:3]=1
A solution of 4-bromo-2-fluorobenzylamine (20.4 g, 0.10 mol) in toluene (300 ml) is saturated with gaseous hydrochloric acid at 25° C. The resulting suspension of the 4-bromo-2-fluorobenzylamine hydrochloride is heated at 100° C. Phosgene is passed in at this temperature. Stirring of the solution, which has eventually become clear, is continued at 100° C. for 1 hour, and the mixture is then refluxed to remove the gases phosgene and hydrogen chloride. The batch is worked up by distillation. 21.2 g of 4-bromo-2-fluorobenzyl isocyanate (boiling point 109° C. at 4 mbar) are obtained. Yield: 92.1% of theory.
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