Novel tricyclic indeno[2,1-d]pyrimidines with dual antiangiogenic and cytotoxic activities as potent antitumor agents.

We designed, synthesized and evaluated 13 novel tricyclic indeno[2,1-d]pyrimidines as RTK inhibitors. These analogues were synthesized via a Dieckmann condensation of 1,2-phenylenediacetonitrile followed by cyclocondensation with guanidine carbonate to afford the 2-amino-3,9-dihydro-indeno[2,1-d]pyrimidin-4-one. Sulfonation of the 4-position followed by displacement with appropriately substituted anilines afforded the target compounds. These compounds were potent inhibitors of platelet-derived growth factor receptor β (PDGFRβ) and inhibited angiogenesis in the chicken embryo chorioallantonic membrane (CAM) assay compared to standards. In addition, compound 7 had a two digit nanomolar GI(50) against nine tumor cell lines, a submicromolar GI(50) against 29 of other tumor cell lines in the preclinical NCI 60 tumor cell line panel. Compound 7 also demonstrated significant in vivo inhibition of tumor growth and angiogenesis in a B16-F10 syngeneic mouse melanoma model.