1-phenyl-1H-pyrazol-3-amine → 5-Nitro-2-phenyl-2H-pyrazolo [3,4-b]pyridine

HRID 901214Notes

Reaction equation

HRID 901214 reaction equation
[C:1]1([N:7]2[CH:11]=[CH:10][C:9]([NH2:12])=[N:8]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.O.[N+:14]([CH:17]([CH:20]=O)[CH:18]=O)([O-:16])=[O:15].[Na]>C(O)(=O)C>[N+:14]([C:17]1[CH:20]=[N:12][C:9]2=[N:8][N:7]([C:1]3[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=3)[CH:11]=[C:10]2[CH:18]=1)([O-:16])=[O:15]

Participants

4

Reactant 2

HCID 5943201-phenyl-1H-pyrazol-3-amineHCID 71317419Sodium nitromalonaldehyde hydrate

Product 1

HCID 586701485-Nitro-2-phenyl-2H-pyrazolo [3,4-b]pyridine

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Compound 3A (3.0 g, 18.868 mmol) and sodium nitromalonaldehyde monohydrate (2.623 g, 18.868 mmol, prepared according to the procedures reported in Org. Synth. IV. 844, (1963)) in acetic acid (100 mL) was refluxed for 24 hours. After cooling to RT, the reaction was concentrated under reduced pressure to remove most of the acetic acid. The resulting residue was dissolved in CH2Cl2 (200 mL), then washed with IN aqueous NaOH (2×200 mL), water (100 mL), saturated NaCl (100 mL). The organic layer was dried (MgSO4), and concentrated to give a dark brown residue. The residue was purified by silica gel column chromatography eluting with 2 M NH3 in MeOH/CH2Cl2 (1:99 ratio) to give the title compound, 5-nitro-2-phenyl-2H-pyrazole[3,4-b ]pyridine as a beige colored solid (300 mg). LC/MS (method A): retention time=2.62 min; (M+H)+=241.

Workup

  1. concentrationthe reaction was concentrated under reduced pressure
  2. customto remove most of the acetic acid
  3. dissolutionThe resulting residue was dissolved in CH2Cl2 (200 mL)
  4. washwashed with IN aqueous NaOH (2×200 mL), water (100 mL), saturated NaCl (100 mL)
  5. dry with materialThe organic layer was dried (MgSO4)
  6. concentrationconcentrated
  7. customto give a dark brown residue
  8. customThe residue was purified by silica gel column chromatography
  9. washeluting with 2 M NH3 in MeOH/CH2Cl2 (1:99 ratio)

Sources & evidence

ORD record
ord-f9b2c6d612a74e17a480761fe180778f
Source dataset
uspto-grants-2008_04
Patent number
US07361766B2

Reaction notes

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