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

HRID 1639613Notes

Reaction equation

HRID 1639613 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-931ab2be03c44f99b8e4c8b707d5b4fc
Source dataset
uspto-grants-2012_02
Patent number
US08110573B2

Reaction notes

Loading…