Hydrochloric Acid → 2,4-Dichloro-5-nitropyridine

To 4-chloro-5-nitropyridine-2-amine (Method 92, 4.40 g, 21.0 mmol) in concentrated HCl (70 ml) was added sodium nitrite (4.36 g, 63.1 mmol) potion wise at 0-5° C. After 1 hour at 0-5° C., the reaction was warmed to room temperature and stirred for 50 hours. Ice (100 g) was added and the mixture was extracted with ether (2×50 ml) and dried over sodium sulfate. The solvent was removed under reduced pressure and the resulted residue was purified by column chromatography (hexane-DCM=1:5) to give the title compound as a white solid (1.47 g, 33%). 1H NMR (400 MHz) 9.18 (s, 1H), 8.22 (s, 1H).

1. extractionthe mixture was extracted with ether (2×50 ml)
2. dry with materialdried over sodium sulfate
3. customThe solvent was removed under reduced pressure
4. customthe resulted residue was purified by column chromatography (hexane-DCM=1:5)

ORD record

ord-a7f26a6cd4da460983d5a143b57660fa

Source dataset

uspto-grants-2012_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08129403B2