3-Hydroxybenzaldehyde → 2-Bromo-5-hydroxybenzaldehyde

To a solution 3-hydroxybenzaldehyde (Aldrich, 101.39 g, 805 mmol) in chloroform (1000 mL), was added bromine (45 mL, 845 mmol) in chloroform (200 mL) drop wise over a period of 2 h at room temperature. The reaction mixture was stirred at room temperature overnight and filtered to collect crude 2-bromo-5-hydroxy benzaldehyde (32 g) as a dark brown solid. The filtrate was concentrated to 200 mL, filtered through a pad of Celite and silica gel (40 g) and washed with ether (1000 mL). The filtrate was concentrated in vacuo to give a second crop of the crude desired aldehyde (60 g) as a dark brown solid. The above solids were combined and dissolved in glacial acetic acid (360 mL) by heating. Water (840 mL) was added and the solution was filtered hot. The solution was allowed to attain room temperature and kept in a refrigerator overnight. The crystals obtained were collected by filtration and washed with water, dried overnight in vacuo to furnish (60 g, 37%) of the desired product as a purplish brown crystalline solid, mp: 135° C.

1. filtrationfiltered
2. customto collect crude 2-bromo-5-hydroxy benzaldehyde (32 g) as a dark brown solid
3. concentrationThe filtrate was concentrated to 200 mL
4. filtrationfiltered through a pad of Celite and silica gel (40 g)
5. washwashed with ether (1000 mL)
6. concentrationThe filtrate was concentrated in vacuo
7. customto give a second crop of the crude desired aldehyde (60 g) as a dark brown solid
8. temperatureby heating
9. filtrationthe solution was filtered hot
10. customto attain room temperature
11. customkept in a refrigerator overnight
12. customThe crystals obtained
13. filtrationwere collected by filtration
14. washwashed with water
15. customdried overnight in vacuo

ORD record

ord-5ae949c5b881469ca752b85fb8b2cb1f

Source dataset

uspto-grants-2005_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06936719B2