5-Nitrofurfural → HCID 178519730, compound

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Reaction Steps

6,7-Difluoro-1H-benzimidazole-2-thiol (0.34 g, 1.81 mmol) is suspended into 20 mL of tetrahydrofuran (THF) under argon. Then, 130 mg (2.71 mmol) of sodium hydride are added. The reaction mixture is stirred at room temperature until gas evolution has ceased. 5-Nitro-2-furaldehyde (0.25 g, 1.81 mmol) is then added and the reaction mixture is stirred at room temperature for 3 h, upon which it is poured on ice and extracted twice with ethyl acetate. The organic extracts are combined, washed with brine, dried on magnesium sulfate, filtered and concentrated under reduced pressure. The residue is purified by chromatography on a prepacked 70 g 15-40 μm silica gel cartridge (eluting solvent: dichloromethane/THF from 100/0 to 80/20 v/v; rate: 40 mL/min). The fractions containing the desired product are combined and concentrated to dryness under reduced pressure. The residue is purified by chromatography on a prepacked 30 g 15-40 μm silica gel cartridge (eluting solvent: dichloromethane/methanol from 100/0 to 95/5 v/v; rate: 20 mL/min). The fractions containing the desired product are combined and concentrated to dryness under reduced pressure. 0.28 g of 5-(6,7-difluoro-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde is obtained as a pale yellow meringue. LCMS-DAD-ELSD: 281(+): [M+H]+.

Provenance & Evidence