3-bromo-2,4,5-trifluorobenzonitrile

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 3-bromo-2,4,5-trifluorobenzonitrile (13.9 g) in concentrated sulfuric acid (8 ml) was heated for 20 minutes on an oil bath (100° C.), poured into ice water (350 ml). The resulting precipitate was collected by filtration and washed with water. The filtrate and washings were extracted 3 times with dichloromethane. The dichloromethane layer was washed with water saturated with sodium chloride, dried over anhydrous sodium sulfate and concentrated to give the residue. The combined mixture of the precipitate obtained previously and the residue was purified by silica gel chromatography eluting with dichloromethane dichloromethane:methanol (10:1) to give 3-bromo-2,4,5-trifluorobenzamide (8.7 g). The resulting precipitate was collected by filtration washed with water The filtrate and washings were extracted 3 times with dichloromethane The dichloromethane layer was washed with water saturated with sodium chloride dried over anhydrous sodium sulfate concentrated to give the residue The combined mixture of the precipitate obtained previously the residue was purified by silica gel chromatography eluting with dichloromethane dichloromethane:methanol (10:1)