β-Carbolinedione Derivatives as Topoisomerase I Inhibitors

Pyrrolo[3,4-c]-β-carbolinedione dimers 5-14 were synthesized from furo[3,4-c]-β-carbolmediones and diamines by solvent-free TaCl 5 /silica catalyzed reaction under microwave irradition. The Inhibitory property of these target compound, the starting materials 2, 31, 32, and the N-alkylated pyrrolo[3,4-c]-β-carbolinediones 16, 17, 20-30 was tested against the relaxation of supercoiled pRB322 DNA by calf thynius topoisomerases I and II. Some of these compounds, especially 7 and 23 proved to be selective inhibitors of topoisomerase I.