Synthesis of hybrid phosphorated indenoquinolines and biological evaluation as topoisomerase I inhibitors and antiproliferative agents.

This work describes the first synthesis of diethyl 6,6a,7,11b-tetrahydro-5H-indeno[2,1-c]quinolinylphosphonates 5, diethyl 7H-indeno[2,1-c]quinolinylphosphonates 6 and diethyl 7-oxo-7H-indeno[2,1-c]quinolinylphosphonates 7, which were prepared in good to high overall yields. The synthetic route involves a multicomponent reaction of 2-phosphonateaniline, aldehydes and indene as olefin and allows the selective generation of three stereogenic centres in a short, efficient and reliable manner. The selective dehydrogenation of 1,2,3,4-tetrahydroindenoquinolines leads to the formation of corresponding indenoquinolines, and subsequent oxidation of methylene group of the indenoquinolines allows the access to indenoquinolinones.