Phosphorus tribromide → 4-(Bromomethyl)-5-cyclopropyl-3-(2,6-dichlorophenyl)isoxazole

Participants

Reaction Steps

Alternate procedure: Cool a solution of (5-cyclopropyl-3-(2,6-dichloro-phenyl)-isoxazol-4-yl)-methanol (100 g, 0.35 mol) in dichloromethane (1200 mL) to −10° C. Add phosphorous tribromide (105 g, 0.39 mol) dropwise while maintaining the internal temperature between −5° C. and 0° C. Stir at −5° C. to 0° C. for 30 min. Allow to warm to between 20° C. and 25° C. and stir at 20° C. to 35° C. for 2 h. Cool the reaction mixture to 0° C. to 5° C. Add an aqueous solution of sodium bicarbonate (775 mL) dropwise. Separate the phases. Extract the aqueous phase with dichloromethane (2×350 mL). Wash the combined organic phases with water (3×500 mL). Concentrate the organic phase to afford 115 g (94%) of the title compound as a solid.

Provenance & Evidence