5-Nitrofurfural → HCID 178488111, compound

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Reaction Steps

2-Mercapto-5-methoxybenzimidazole (1.8 g, 10.0 mmol) is suspended into 25 mL of tetrahydrofuran (THF) under argon. Then, 575 mg (12.0 mmol) of sodium hydride are added. The reaction mixture is stirred at room temperature until gas evolution has ceased. A solution of 5-nitro-2-furaldehyde (1.4 g, 10.0 mmol) in 30 mL of THF is then added dropwise and the reaction mixture is stirred at room temperature for 2 h, upon which it is poured on ice and extracted 3 times with 50 mL of ethyl acetate. The organic extracts are combined, washed with brine, dried on magnesium sulfate, filtered and concentrated under reduced pressure. The residue is triturated in diisopropyl ether and the resulting suspension is stirred for 1 h. The solid is filtered, washed twice with diisopropyl ether and dried. 0.75 g of 5-(5-methoxy-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde is obtained as a pale yellow powder. The filtrate is concentrated under reduced pressure and the residue is purified by chromatography on a prepacked 90 g 15-40 μm silica gel cartridge (eluting solvent: ethyl acetate). The fractions containing the desired product are combined and concentrated to dryness under reduced pressure. 0.92 g of additional 5-(5-methoxy-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde is obtained as a pale yellow powder. mp: 94-99° C.

Provenance & Evidence