Benz[b]oxepines 4a-g and 12-oxobenzo[c]phenanthridines 5a-d were designed and synthesized as constrained forms of 3-arylisoquinolines through an intramolecular radical cyclization reaction. Radical cyclization of O-vinyl compounds preferentially led to the 7-endo-trig cyclization pathway to the benz[b]oxepines and 12-oxobenzo[c]phenanthridines through 6-exo-trig path as minor products. Among the synthesized compounds, benz[b]oxepine derivative 4e exhibited potent in vitro cytotoxicity against three different tumor cell lines, as well as topoisomerase 1 inhibitory activity. A Surflex-Dock docking study was performed to clarify the topoisomerase 1 activity of 4e.
Bibliographical noteFunding Information:
This work was supported by a Korea Research Foundation Grant (KRF-2007-521-E00190).
- Docking study
- Molecular modeling
- Radical cyclization
- Topoisomerase 1