Sulfuric Acid → 2,6-Dibromo-3-nitropyridin-4-amine

Temperatur

54 °C

Concentrated sulphuric acid (250 ml) was heated in an oil bath until the temperature of the acid reached 47° C. 2,6-dibromo pyridin-4-yl-N-nitroamine (34.0 g, 114.5 mmol) was added in portions over 35 mins. The temperature of the mixture gradually rose throughout the addition period until it was 56° C. at the end. The mixture was stirred at 53-55° C. for 1 hour. Once the reaction was completed, the reaction mixture was cooled to in an ice-bath and poured on ˜2 L of crushed ice with stirring. The product precipitated and was filtered off. Combined with other batch 00110916-140-001 from an identical scale reaction. The crude, wet amino nitro pyridine was dissolved in 700 ml EtOAc and the water layer was separated. The organic layer was washed with water (2×150 ml), 1×150 ml aq. NaHCO3, brine (2×150 ml), dried (MgSO4) and concentrated under reduced pressure to give 28 g of the title compound.

1. customreached 47° C
2. additionThe temperature of the mixture gradually rose throughout the addition period until it
3. customwas 56° C. at the end
4. temperaturethe reaction mixture was cooled to in an ice-bath
5. stirringwith stirring
6. customThe product precipitated
7. filtrationwas filtered off
8. customCombined with other batch 00110916-140-001 from an identical scale reaction
9. customthe water layer was separated
10. washThe organic layer was washed with water (2×150 ml), 1×150 ml aq. NaHCO3, brine (2×150 ml)
11. dry with materialdried (MgSO4)
12. concentrationconcentrated under reduced pressure

ORD-Eintrag

ord-2db24d8d665a40fab614d5fdc2764f27

Quelldatensatz

uspto-grants-2010_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07691877B2