Acetic Acid → 4-(Bromomethyl)-1,2-diethylbenzene

Temperature

80 °C

1,2-Diethylbenzene (3.4 g, 23.3 mmol) and paraformaldehyde (2.5 g, 84 mmol) were suspended in glacial acetic acid (60 mL), hydrobromic acid (38% in acetic acid, 8 mL) was added, the reaction flask was sealed with a rubber septum and heated to 80° C. After 4 hours the solution was cooled to ambient temperature and paraformaldehyde (2.5 g, 84 mmol) and hydrobromic acid (38% in acetic acid, 8 mL) were added. The mixture was reheated to 80° C. for 4 hours. Further paraformaldehyde (2.5 g, 84 mmol) and hydrobromic acid (38% in acetic acid, 8 mL) were and the reaction let stir at 80° C. overnight. After a total of 24 hours of reaction time the solution was cooled, diluted with water and diethyl ether, then the layers separated. The organic layers were washed carefully with saturated sodium bicarbonate (4×50 mL), brine, then dried with sodium sulfate, filtered and concentrated in the presence of silica. Purified by column chromatography eluting with 100% hexanes. Concentrated fractions to a yield 4-(bromomethyl)-1,2-diethylbenzene (4.05 g, 77%) 1H NMR (300 MHz, CDCl3) δ 1.21 (m, 6H) 2.64 (m, 4H), 4.47 (s, 2H), 7.1-7.2 (m, 3H).

1. customthe reaction flask was sealed with a rubber septum
2. temperatureAfter 4 hours the solution was cooled to ambient temperature
3. customAfter a total of 24 hours of reaction time the solution
4. temperaturewas cooled
5. customthe layers separated
6. washThe organic layers were washed carefully with saturated sodium bicarbonate (4×50 mL), brine
7. dry with materialdried with sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated in the presence of silica
10. customPurified by column chromatography
11. washeluting with 100% hexanes

ORD record

ord-ba2447adf13c4ec9a92cd01b10d1f797

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08604023B2