5-Methyl-2-nitro-4,5,6,7-tetrahydropyrazolo[1,5-A]pyrazine → 5-methyl-4H,5H,6H,7H-pyrazolo[1,5-a]pyrazin-2-amine

HRID 872142Notes

Reaction equation

HRID 872142 reaction equation
[CH3:1][N:2]1[CH2:7][CH2:6][N:5]2[N:8]=[C:9]([N+:11]([O-])=O)[CH:10]=[C:4]2[CH2:3]1>C(O)C>[CH3:1][N:2]1[CH2:7][CH2:6][N:5]2[N:8]=[C:9]([NH2:11])[CH:10]=[C:4]2[CH2:3]1

Participants

3

Reactant 1

HCID 580440245-Methyl-2-nitro-4,5,6,7-tetrahydropyrazolo[1,5-A]pyrazine

Product 1

HCID 580439335-methyl-4H,5H,6H,7H-pyrazolo[1,5-a]pyrazin-2-amineYield 988.6%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A 500-mL Parr reactor bottle was purged with nitrogen and charged with 10% palladium on carbon (50% wet, 800 mg dry weight) and a solution of 5-methyl-2-nitro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine 101k (4.00 g, 2.20 mmol) in ethanol (160 mL). The bottle was attached to Parr hydrogenator, evacuated, charged with hydrogen gas to a pressure of 45 psi and shaken for 2 h. After this time, the hydrogen was evacuated, and nitrogen was charged into the bottle. Celite 521 (1.0 g) was added, and the mixture was filtered through a pad of Celite 521. The filter cake was washed with ethanol (2×75 mL), and the combined filtrates were concentrated to dryness under reduced pressure to afford a 99% yield of 5-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-2-amine (101l) (3.31 g) as an orange solid: 1H NMR (300 MHz, CDCl3) δ 5.34 (s, 1H), 3.98 (t, 2H, J=5.4 Hz), 3.52 (s, 3H), 2.84 (t, 2H, J=5.7 Hz), 2.45 (s, 3H); MS (ESI+) m/z 153.1 (M+H).

Workup

  1. customA 500-mL Parr reactor bottle was purged with nitrogen
  2. additioncharged with 10% palladium on carbon (50% wet, 800 mg dry weight)
  3. customevacuated
  4. additioncharged with hydrogen gas to a pressure of 45 psi
  5. customAfter this time, the hydrogen was evacuated
  6. additionnitrogen was charged into the bottle
  7. additionCelite 521 (1.0 g) was added
  8. filtrationthe mixture was filtered through a pad of Celite 521
  9. washThe filter cake was washed with ethanol (2×75 mL)
  10. concentrationthe combined filtrates were concentrated to dryness under reduced pressure

Sources & evidence

ORD record
ord-e915d5cdf03d4619b5e4c64370339a40
Source dataset
uspto-grants-2015_03
Patent number
US08975260B2

Reaction notes

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