CONDENSED IMIDAZO-1,2,4-AZINES. 15. REACTION OF 1,2-DIAMINOBENZIMIDAZOLE WITH 5-PHENYL-2,3-DIHYDROFURAN-2,3-DIONE

Article abstract of DOI:10.1007/BF00546744

The reaction of 1,2-diaminobenzimidazole with 5-phenyl-2,3-dihydrofuran-2,3-dione in acetic acid gave a mixture of 2-benzoylmethyl-1,2,4-triazino<2,3-a>benzimidazol-4H-3-one and 3-benzoylmethyl-1,2,4-triazino<2,3-a>benzimidazol-1H-2-one, the intramolecular cyclization of which gave isomeric 2-phenylfuro<5,4-e>- and 2-phenylfuro<4,5-e>-1,2,4-triazino<2,3-a>benzimidazoles.Only the corresponding furo<4,5-e>-1,2,4-triazino<2,3-a>benzimidazole was isolated when the reaction was carried out in sulfuric acid.