3-Methylbenzoic acid → 3-(Bromomethyl)benzoic acid

Participants

Reaction Conditions

Reaction Steps

In a 1 L round bottom flask fitted with a reflux condenser, a stirred suspension of 10.00 g of m-toluic acid and 14.37 g (1.1 eq.) N-bromosuccinimide in 735 mL chloroform was sparged for 0.5 h with nitrogen. The sparging was discontinued, and the suspension was stirred and irradiated under nitrogen atmosphere using a 500 W quartz halogen lamp at 75% power, causing the solids to dissolve and the chloroform to reflux. The red color of the reaction mixture disappeared after 1.25 h, and 14.37 g of N-bromosuccinimide was added. The reaction mixture was stirred and irradiated under nitrogen atmosphere with a 500 W quartz halogen lamp at 75% power for another 1.5 h, at which time the solution became colorless. The solvent volume was reduced in vacuo to about 100 mL, and then cooled to −20° C. The resultant suspension was vacuum filtered through a bed of dry silica. The silica was washed with 800 mL of chloroform. The chloroform filtrate was reduced in vacuo to about 100 mL, and then cooled to −20° C. The resultant crystals were vacuum filtered, washed with 30 mL of chloroform followed by 50 mL of hexanes, then dissolved in 250 mL chloroform and washed in a separatory funnel with 3×300 mL volumes of water followed by one 300 mL volume of brine to remove traces of succinimide. The organic phase was dried with magnesium sulfate, vacuum filtered, and the solvent was removed in vacuo to provide 9.56 g (61%) of 3-bromomethylbenzoic acid as a white crystalline power.

Provenance & Evidence