Acetic Acid → 5-bromo-3-(2-chloro-4-hydroxybenzyl)-2-methyl-3H-imidazo[4,5-b]pyridine

Temperature

110 °C

To a solution of 2-[N-(4-acetoxy-2-chlorobenzyl)acetamido]-6-bromo-3-nitropyridine (1.28 g) in ethanol (13 ml) were added acetic acid (1.5 ml) and reduced iron powder (646 mg), and the mixture was refluxed under heating at 110° C. for 15 hr. After allowing to cool, chloroform/methanol=10/1 (15 ml) was added and the mixture was stirred under ice-cooling. The insoluble matter was filtered off and the filtrate was concentrated. A saturated aqueous sodium hydrogen carbonate solution (5 ml) and chloroform/methanol=10/1 (15 ml) were added to make the mixture alkaline, and the precipitated insoluble matter was filtered off. The residue was repeatedly eluted with chloroform/methanol=5/1-2/1-1/1. The organic layer of the filtrate was washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate, filtered and concentrated. To the resulting crystals was added ethyl acetate (8 ml), and the mixture was heated and stirred at room temperature. The crystals were collected by filtration and dried under reduced pressure to give 5-bromo-3-(2-chloro-4-hydroxybenzyl)-2-methyl-3H-imidazo[4,5-b]pyridine as colorless crystals (1.04 g).

1. temperaturethe mixture was refluxed
2. temperatureto cool
3. temperaturecooling
4. filtrationThe insoluble matter was filtered off
5. concentrationthe filtrate was concentrated
6. additionA saturated aqueous sodium hydrogen carbonate solution (5 ml) and chloroform/methanol=10/1 (15 ml) were added
7. filtrationthe precipitated insoluble matter was filtered off
8. washThe residue was repeatedly eluted with chloroform/methanol=5/1-2/1-1/1
9. washThe organic layer of the filtrate was washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine
10. dry with materialdried over anhydrous magnesium sulfate
11. filtrationfiltered
12. concentrationconcentrated
13. additionTo the resulting crystals was added ethyl acetate (8 ml)
14. temperaturethe mixture was heated
15. stirringstirred at room temperature
16. filtrationThe crystals were collected by filtration
17. customdried under reduced pressure

ORD record

ord-2a016b1f09b2414495ebcd5b8897838b

Source dataset

uspto-grants-2005_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06890934B2