Synthesis of benz[d]indeno[1,2-b]pyran-5,11-diones: Versatile intermediates for the design and synthesis of topoisomerase I inhibitors

A method has been developed that relies on a two-step, one-pot condensation between phthalide and 2-carboxybenzaldehydes to provide benz[d]indeno[1,2-b]pyran-5,11-diones in a multi-gram fashion. Treatment of these compounds with a primary amine allows rapid access to various N-substituted indenoisoquinolines, whose in vitro anticancer activity and topoisomerase I inhibition have been evaluated.

Graphical abstractA one-pot, two-step synthesis of indenopyrans and their conversion to indenoisoquinoline topoisomerase I inhibitors are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide