Hydrogen Bromide → 3-Methoxybenzyl bromide

To cooled (15° to 20° C.) hydrobromic acid (3.22 kg) (48%) is added 3-methoxybenzyl alcohol (1 kg) dropwise over a period of 1 hour. A slight exotherm results with pot temperature rising from 20° to 23° C. After the addition, the reaction mixture was stirred at 23° to 27° C. for four days. The product separated as an oil during this period. The reaction mixture was transferred to a separatory funnel, and the lower layer containing the product was separated. The aqueous phase was extracted with methylene chloride (750 mL). The methylene chloride extract was combined with the main product and washed with water (500 mL×3). The pH of the last wash was 6.5 to 7.0. The product was dried over anhydrous sodium sulfate (200 g), filtered and concentrated under reduced pressure (bath temperature 50° to 55° C.) to remove most of the solvent, then further concentrated at 40° to 45° C. under 5 mm Hg to constant weight to yield 1.30 kg (89% yield) of crude product. The presence of 5.5% of starting material in this product does not interfere with the subsequent alkylation reaction.

1. customA slight exotherm results with pot temperature
2. customrising from 20° to 23° C
3. additionAfter the addition
4. customThe product separated as an oil during this period
5. customThe reaction mixture was transferred to a separatory funnel
6. additionthe lower layer containing the product
7. customwas separated
8. extractionThe aqueous phase was extracted with methylene chloride (750 mL)
9. extractionThe methylene chloride extract
10. washwashed with water (500 mL×3)
11. washThe pH of the last wash
12. dry with materialThe product was dried over anhydrous sodium sulfate (200 g)
13. filtrationfiltered
14. concentrationconcentrated under reduced pressure (bath temperature 50° to 55° C.)
15. customto remove most of the solvent
16. concentrationfurther concentrated at 40° to 45° C. under 5 mm Hg to constant weight

ORD record

ord-b75e4dee00df4083aa7234a889916c8f

Source dataset

uspto-grants-1991_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05001238