抄録
Reaction of benzimidazole and N-acetylbenzimidazole with diketene in acetic acid or acetic anhydride at room temperature resulted in the formation of 2-acetonyl-1, 3-diacetyl-2, 3-dihydrobenzimidazole (II), and 5-acetyl-4a, 5-dihydropyrido [1, 2-a] benzimidazol-1, 3 (2H, 4H)-dione. On the other hand, reactions of 2-ethoxycarbonylmethylbenzimidazole (XIIIa), 2-carbamoylmethylbenzimidazole (XIIIb), 2-cyanomethylbenzimidazole (XIIIc) with diketene in acetic acid at room temperature resulted in the formation of 4-substituted-3-methylpyrido [1, 2-a] benzimidazol-1 (5H)-one (XIIIa-c) in good yields, respectively.
