Research on the reaction of furil with ammonium acetate

The direct reaction of furil with ammonium acetate in refluxing glacial acetic acid under the absence of appropriate aldehydes was systematically studied. The principal product with furan rings and imidazole ring 2,4,5-tri(furan-2-yl)-1H-imidazole (I) was obtained in moderate yield, and two new byproducts containing furan rings were successfully purified by C18 reversed phase column. All compounds were characterized by elemental analysis, MS, IR, 1H and 13C NMR spectroscopy. The structure of I was further confirmed by the 13C-1H COSY spectroscopy. The putative reaction mechanism via stable 1,2-di(furan-2-yl)ethane-1,2-diimine, furan-2-yl-(2,4,5-tri-furan-2-yl-2H-imidazol-2-yl)-methanone and intermediate 5 traced by GC-MS was proposed.