反应详情

A solution of 2-mercapto-5-chloro-6-fluoro-benzimidazole (1.2 g, 5.92 mmol) in tetrahydrofuran (10 ml) is added dropwise to a mixture of sodium hydride (60% dispersion in mineral oil, 0.379 g, 9.47 mmol) and tetrahydrofuran (5 ml). The mixture is stirred at room temperature for 2 hours. A solution of 5-nitro-2-furaldehyde (0.836 g, 5.92 mmol) in tetrahydrofuran (15 ml) is then added dropwise over a 15 minute period and the mixture is stirred for 16 hours at room temperature. The reaction mixture is concentrated under reduced pressure and the residue is dissolved in 100 ml of ethyl acetate and washed with water (2×30 ml). The organic phase is dried over MgSO4 and concentrated under reduced pressure. The residue is purified on a silica gel column (120 g) eluted with a mixture of dichloromethane and methanol (98/2, v/v) to yield 370 mg of 5-(6-chloro-5-fluoro-1H-benzimidazol-2-ylsulfanyl)-furan-2-carbaldehyde as an orange powder. Yield=21%. Analytical LC/MS (method B): retention time=3.58 min., m/z=296.98 (1 Cl, positive ion mode).

1. stirringthe mixture is stirred for 16 hours at room temperature
2. concentrationThe reaction mixture is concentrated under reduced pressure
3. dissolutionthe residue is dissolved in 100 ml of ethyl acetate
4. washwashed with water (2×30 ml)
5. dry with materialThe organic phase is dried over MgSO4
6. concentrationconcentrated under reduced pressure
7. customThe residue is purified on a silica gel column (120 g)
8. washeluted with a mixture of dichloromethane and methanol (98/2