Hydrogen Bromide → 5-(2-bromoacetyl)-4-methylisobenzofuran-1(3H)-one

Participants

Reaction Conditions

Reaction Steps

To a 1 L 3-neck flask equipped with overhead stirrer was added crude 5-(1-butoxy-vinyl)-4-methyl-3H-isobenzofuran-1-one (55.8 g) and THF (315 mL). The solution was cooled to <5° C. after which water (79 mL) was added and the solution was maintained at <5° C. NBS (41.6 g) was then added portionwise while maintaining Tmax=19° C. The solution was then warmed to room temperature for 30 minutes. HBr (48%, 0.241 mL) was added and the reaction was aged at room temperature for approximately 1 hour after which 236 mL water was then added to the batch. A water bath was used to maintain temp at 20° C. Another 315 mL of water was added (solvent composition 1:2 THF:water) and the slurry was cooled to 15° C. The resulting solids were filtered and washed with a cold 1:2 THF:water (15° C.): 150 mL displacement wash followed by 100 mL slurry wash. The solids were dried under vacuum at room temperature to provide 5-(2-bromo-acetyl)-4-methyl-3H-isobenzofuran-1-one.

Provenance & Evidence