Furan ring transformation as key stage in the synthesis of 5H,12H-benzo[4,5]imidazo[1,2-a]pyrrolo[1,2-d]pyrazines

摘要

We report the first synthesis of new condensed benzimidazole derivatives - 5H,12H-benzo[4,5]imidazo[1,2-a]pyrrolo[1,2-d]pyrazines, based on furan ring transformation in 1-[(5-alkylfuran-2-yl)methyl]-2-(chloromethyl)benzimidazoles. Two routes are presented for the formation of pyrrolopyrazine system, with different order of steps for the introduction of amino group and opening of the furan ring.