5,6-Dimethoxy-2-(4-nitro-1,2-dihydro-3H-pyrazol-3-ylidene)-2H-benzimidazole → HCID 178486794, compound

HRID 1946251Notes

Reaction equation

HRID 1946251 reaction equation
[CH3:1][O:2][C:3]1[C:19]([O:20][CH3:21])=[CH:18][C:6]2[NH:7][C:8]([C:10]3[C:14]([N+:15]([O-])=O)=[CH:13][NH:12][N:11]=3)=[N:9][C:5]=2[CH:4]=1>[Pd].C(O)C.CN(C=O)C>[CH3:21][O:20][C:19]1[C:3]([O:2][CH3:1])=[CH:4][C:5]2[NH:9][C:8]([C:10]3[C:14]([NH2:15])=[CH:13][NH:12][N:11]=3)=[N:7][C:6]=2[CH:18]=1

Participants

5

Reactant 1

HCID 1784867955,6-Dimethoxy-2-(4-nitro-1,2-dihydro-3H-pyrazol-3-ylidene)-2H-benzimidazole

Product 1

HCID 178486794HCID 178486794, compoundYield 53.6%

Reagents, catalysts & solvents 3

HCID 23938PalladiumCatalystHCID 702EthanolSolventHCID 6228DimethylformamideSolvent

Procedure

A mixture of 5,6-dimethoxy-2-(4-nitro-1H-pyrazol-3-yl)-1H-benzimidazole (2.08 g, 7.2 mmol) and 10% palladium on carbon (200 mg) in ethanol (150 ml) and DMF (50 ml) was hydrogenated at room temperature and pressure overnight. The reaction mixture was filtered through Celite and the solvent removed in vacuo. The resulting solid was azeotroped with methanol and toluene and the solvent removed in vacuo. The crude material was purified by flash chromatography, eluting with DCM: MeOH: acetic acid:water (120:18:3:2) [DMAW120] followed by DCM: MeOH: acetic acid:water (90:18:3:2) (DMAW90). Product fractions were combined and the solvent removed in vacuo to yield 3-(5,6-dimethoxy-1H-benzimidazol-2-yl)-1H-pyrazol-4-ylamine (˜1 g, 53%).

Workup

  1. customwas hydrogenated at room temperature
  2. custompressure overnight
  3. filtrationThe reaction mixture was filtered through Celite
  4. customthe solvent removed in vacuo
  5. customThe resulting solid was azeotroped with methanol and toluene
  6. customthe solvent removed in vacuo
  7. customThe crude material was purified by flash chromatography
  8. washeluting with DCM: MeOH: acetic acid:water (120:18:3:2) [DMAW120]
  9. customthe solvent removed in vacuo

Sources & evidence

ORD record
ord-69afe018a84a4f80a54b3325f35eb4d3
Source dataset
uspto-grants-2013_03
Patent number
US08399442B2

Reaction notes

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