Boron tribromide → 5-Bromo-2,3-dihydroxybenzaldehyde

Temperature

25 °C

To dichloromethane (400 mL) was added 5-bromo-2-hydroxy-3-methoxy-benzaldehyde (prepared per Synthetic Communications, 1991 ;21 (8,9):1091-5; 94.6 g, 409.4 mmol). To this was added with cooling to 10° C. a solution of boron tribromide (153.9 g, 614 mmol) in dichloromethane (400 mL) over 20 minutes, followed by warming to 25° C. overnight. The mixture was poured into 2 L of ice and extracted with chloroform. The chloroform solution was washed with brine, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated in vacuo and hexane was added giving a crystalline precipitate which was filtered, washed with hexane, and dried in vacuo to a solid, 80.0 g, 90% yield. NMR spectraand elemental analysis were consistent with the structure.

1. additionTo this was added
2. extractionextracted with chloroform
3. washThe chloroform solution was washed with brine
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationfiltered
6. concentrationThe filtrate was concentrated in vacuo and hexane
7. additionwas added
8. customgiving a crystalline precipitate which
9. filtrationwas filtered
10. washwashed with hexane
11. customdried in vacuo to a solid, 80.0 g, 90% yield

ORD record

ord-3452986d4a844b9b8d4391f40d657e49

Source dataset

uspto-grants-2002_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06440962B2