Benzimidazole → 3-Benzimidazolylchromone

関与物質

反応手順

Benzimidazole (472 mg) and DBU (608 mg) were dissolved in acetonitrile (20 ml), and stirred at room temperature for 1 hour. To the resulting solution, a solution of 2,3-epoxychromone (162 mg) in dimethylformamide (5 ml) was added dropwise, and the whole was stirred for 5 minutes. After ice water was added, the reaction mixture was extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was fractionatedby silica gel column chromatography (ethyl acetate/hexane=1:3) to give the titled compound (122 mg; yield=93%). Melting point: 154° C. Mass spectrum (M+): 262. 1H-NMR(CDCl3, δ ppm): 8.21 (s, 1H, H2), 8.33 (dd, 1H, H5), 7.52 (t, 1H, H6), 7.80 (t, 1H, H7), 7.61 (d, 1H, H8), 8.35 (s, 1H, H2'), 7.33 (m, 3H, H4', 5', 6'), 7.86 (d, 1H, H7').

情報源と証拠