5-Nitrofurfural → 5-(6-trifluoromethyl-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde

참여 물질

반응 단계

Aldehyde intermediate preparation: 2-mercapto-6-trifluoromethyl-1H-benzimidazole (0.65 g, 2.98 mmol) dissolved in 5 ml of anhydrous tetrahydrofuran is added dropwise to a suspension of sodium hydride (60% dispersion in mineral oil, 0.095 g, 3.16 mmol) in anhydrous tetrahydrofuran (2 ml) over a 20 minutes period. The reaction mixture is stirred for 2 hours at room temperature. Then 5-nitro-2-furaldehyde (0.42 g, 2.98 mmol) dissolved in 5 ml of anhydrous tetrahydrofuran is added dropwise over a 15 minutes period and the reaction mixture is stirred at room temperature for an additional 16 hours period. Sodium hydride (67 mg, 2.23 mmol) is then added and the reaction mixture is stirred for an additional 2 hours period at room temperature. The reaction mixture is then concentrated under reduced pressure, dissolved in ethyl acetate (50 ml) and washed with water (2×10 ml). The organic phase is dried over MgSO4, concentrated under reduced pressure and the residue is triturated in diisopropylether, collected by filtration and dried under vacuum to yield 720 mg of 5-(6-trifluoromethyl-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde as a beige powder. Yield=77%, Analytical LC/MS (method B): retention time=3.73 min., m/z=313.01 (positive ion mode).

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