Cinnamoyl Chloride → (E)-1-(3-Pyridyl)-2-styryl-1H-benzimidazole

Participants

Reaction Steps

To a stirred suspension of N-(3-pyridyl)-o-phenylenediamine (0.93 g, 5 mmol; Kirsch, P.; Schoenleben-Janas, A.; Schirmer, R. H. Liebigs Ann. Org. Bioorg. Chem., 1995, 7, 1275) in xylene (60 ml) was added (E)-cinnamoyl chloride (0.83 g, 5 mmol). After stirring at the room temperature for 1h, the resulting mixture was heated to reflux removing water using a Dean-Stark apparatus for 11 h. After cooling, the reaction mixture was concentrated to dryness. The residue was dissolved into ethyl acetate (100 ml), washed consecutively with saturated aqueous sodium bicarbonate solution (50 ml) and brine (50 ml), dried (magnesium sulfate) and concentrated to dryness. The residue was purified by column chromatography (silica gel, 165 g; n-hexane/ethyl acetate (3/2 to 1/1)) to give 0.77 g (34%) of brown solids. Recrystallization from isopropyl ether yielded 0.50 g of the titled compound as pink solids. MW: 297.36; mp: 118.0-118.5° C.; 1H-NMR (CDCl3) δ: 8.84 (1H, dd, J=4.8, 1.5 Hz), 8.79 (1H, d, J=2.6 Hz), 8.00 (1H, d, J=15.8 Hz), 7.88-7.79 (2H, m), 7.61 (1H dd, J=8.1, 4.8 Hz), 7.50-7.44 (2H, m), 7.39-7.15 (6H, m), 6.78 (1H, d, J=15.8 Hz).

Provenance & Evidence