Hydrochloric Acid → 3,4-diamino-1-phenyl-1H-pyrazole

To a solution of 3-amino-4-nitro-1-phenyl-1H-pyrazole (200 mg, 0.98 mmol) in methanol (30 mL) were added conc. hydrochloric acid (0.5 mL) and 10% palladium-carbon (20 mg), and the mixture was stirred for 1.5 hours at room temperature under a hydrogen atmosphere. After removal of the catalyst by filtration, the filtrate was concentrated, and aqueous sodium bicarbonate solution was added to the resulting residue. The solution was extracted 5 times with chloroform, and the chloroform layer was dried over anhydrous magnesium sulfate, and then concentrated in vacuo. Diisopropyl ether was added to the resulting residue, and the precipitates were collected by filtration and dried to obtain the title compound (101 mg, 58.6%).

1. customAfter removal of the catalyst
2. filtrationby filtration
3. concentrationthe filtrate was concentrated
4. additionaqueous sodium bicarbonate solution was added to the resulting residue
5. extractionThe solution was extracted 5 times with chloroform
6. dry with materialthe chloroform layer was dried over anhydrous magnesium sulfate
7. concentrationconcentrated in vacuo
8. additionDiisopropyl ether was added to the resulting residue
9. filtrationthe precipitates were collected by filtration
10. customdried

ORD record

ord-429f976212b349a8948fc63556fa3d8b

Source dataset

uspto-grants-2009_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07589096B2