Hydrochloric Acid → 4-bromo-2-(chloromethyl)-1-methylbenzene

Temperature

2.5 °C

To a mixture of 80.9 g (0.406 mol) of 5-bromo-2-methylbenzaldehyde and 7.80 g (0.206 mol) of NaBH4 in 300 ml of THF 200 ml of methanol was added dropwise by vigorous stirring for 5 h at 0-5° C. This mixture was stirred overnight at room temperature and then added to 1 liter of cold water. The resulting mixture was acidified by 2 M HCl to pH˜1, and the formed (5-bromo-2-methylphenyl)methanol was extracted with 3×250 ml of dichloromethane. The combined organic extract was dried over Na2SO4 and evaporated to dryness. To the residue dissolved in 450 ml of dichloromethane 37 ml of SOCl2 was added dropwise at +5° C. The resulting solution was stirred overnight at room temperature, evaporated to dryness, the residue was dissolved in 500 ml CH2Cl2, and the obtained solution was washed with 500 ml of water. The organic layer was separated, the aqueous layer was additionally extracted with 2×100 ml of dichloromethane. The combined organic extract was passed through a short pad of silica gel 60 (40-63 um), the filtrate was evaporated to dryness, and the residue was dried in vacuum to yield 5-bromo-2-methylbenzyl chloride as a slightly yellowish liquid which was further used without an additional purification.

1. additionwas added dropwise
2. stirringThis mixture was stirred overnight at room temperature
3. extractionthe formed (5-bromo-2-methylphenyl)methanol was extracted with 3×250 ml of dichloromethane
4. extractionThe combined organic extract
5. dry with materialwas dried over Na2SO4
6. customevaporated to dryness
7. dissolutionTo the residue dissolved in 450 ml of dichloromethane 37 ml of SOCl2
8. additionwas added dropwise at +5° C
9. stirringThe resulting solution was stirred overnight at room temperature
10. customevaporated to dryness
11. dissolutionthe residue was dissolved in 500 ml CH2Cl2
12. washthe obtained solution was washed with 500 ml of water
13. customThe organic layer was separated
14. extractionthe aqueous layer was additionally extracted with 2×100 ml of dichloromethane
15. extractionThe combined organic extract
16. customthe filtrate was evaporated to dryness
17. customthe residue was dried in vacuum

ORD record

ord-86ccb2294a5a40ed9ab3a28144e4a281

Source dataset

uspto-grants-2015_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09187583B2