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

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Reaction Steps

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%).

Provenance & Evidence