1-Cyclopropyl-4-nitro-1H-pyrazole → 1-Cyclopropyl-1H-pyrazol-4-amine

A 250-mL Parr reactor bottle was purged with nitrogen and charged with 10% palladium on carbon (50% wet, 117 mg dry weight) and a solution of 109a (500 mg, 6.73 mmol) in ethanol (36 mL). The bottle was attached to a Parr hydrogenator, evacuated, charged with hydrogen gas to a pressure of 50 psi and shaken for 2 h. After this time, the hydrogen was evacuated, and nitrogen was charged into the bottle. Celite 521 (1.00 g) was added, and the mixture was filtered through a pad of Celite 521. The filter cake was washed with ethanol (2×25 mL), and the combined filtrates were concentrated to dryness under reduced pressure to afford a 94% yield of 109b (378 mg) as a purple oil: 1H NMR (300 MHz, CDCl3) δ 7.13 (s, 1H), 7.07 (s, 1H), 3.47 (m, 1H), 2.87 (br s, 2H), 0.96 (m, 4H); MS (ESI+) m/z 124.1 (M+H).

1. customA 250-mL Parr reactor bottle was purged with nitrogen
2. additioncharged with 10% palladium on carbon (50% wet, 117 mg dry weight)
3. customevacuated
4. additioncharged with hydrogen gas to a pressure of 50 psi
5. customAfter this time, the hydrogen was evacuated
6. additionnitrogen was charged into the bottle
7. additionCelite 521 (1.00 g) was added
8. filtrationthe mixture was filtered through a pad of Celite 521
9. washThe filter cake was washed with ethanol (2×25 mL)
10. concentrationthe combined filtrates were concentrated to dryness under reduced pressure

ORD record

ord-4b8047a3a1414016a7ccdcc691c58f5d

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09249123B2