Hydrogen Bromide → 2,3-Dihydroxybenzaldehyde

Into a 500 ml round bottom flask fitted with a nitrogen inlet, condenser, and a magnetic stirring bar were placed o-vanillin (50 g, 330 mmol), 200 ml glacial acetic acid, and 60 ml of 48% hydrobromic acid. The mixture was heated to reflux and allowed to stir for 18 hours. The solvent was distilled off and the residue was taken up in methanol and filtered. The filtrate was concentrated and the residue taken up in methylene chloride. This solution was washed three times with sodium bicarbonate, twice with brine, dried over sodium sulfate, filtered, and concentrated. The crude product was dissolved in 0-2% methanol in methylene chloride and chromatographed (100:10:1 methylene chloride:methanol:ammonium hydroxide) to give 12.49g. of subtitled product (27%) which was used directly in the next step.

1. customInto a 500 ml round bottom flask fitted with a nitrogen inlet, condenser, and a magnetic stirring bar
2. temperatureThe mixture was heated
3. temperatureto reflux
4. distillationThe solvent was distilled off
5. filtrationfiltered
6. concentrationThe filtrate was concentrated
7. washThis solution was washed three times with sodium bicarbonate
8. dry with materialtwice with brine, dried over sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated
11. dissolutionThe crude product was dissolved in 0-2% methanol in methylene chloride
12. customchromatographed (100:10:1 methylene chloride:methanol:ammonium hydroxide)
13. customto give 12.49g

ORD record

ord-92660cefea7a45c983c036555ef1f917

Source dataset

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06376505B1