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

Temperature

-20 °C

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.

1. customIn a 1 L round bottom flask fitted with a reflux condenser
2. customwas sparged for 0.5 h with nitrogen
3. customirradiated under nitrogen atmosphere
4. dissolutionto dissolve
5. temperaturethe chloroform to reflux
6. addition14.37 g of N-bromosuccinimide was added
7. stirringThe reaction mixture was stirred
8. customirradiated under nitrogen atmosphere with a 500 W quartz halogen lamp at 75% power for another 1.5 h, at which time the solution
9. filtrationfiltered through a bed of dry silica
10. washThe silica was washed with 800 mL of chloroform
11. temperaturecooled to −20° C
12. filtrationfiltered
13. washwashed with 30 mL of chloroform
14. dissolutiondissolved in 250 mL chloroform
15. washwashed in a separatory funnel with 3×300 mL volumes of water
16. customto remove traces of succinimide
17. dry with materialThe organic phase was dried with magnesium sulfate, vacuum
18. filtrationfiltered
19. customthe solvent was removed in vacuo

ORD record

ord-bdc9c136b4df43c3ab541f6dc00ad5b9

Source dataset

uspto-grants-2008_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07432369B2