Organotin flufenamates: Synthesis, characterization and antiproliferative activity of organotin flufenamates

Three novel flufenamates [Me2(flu)SnOSn(flu)Me2]2 (1), [Bu2(flu)SnOSn(flu)Bu2]2 (2) and [Bu2Sn(flu)2] (3) have been prepared and structurally characterized by means of vibrational and NMR (1H, 13C and 119Sn) spectroscopy. Based on spectroscopic data, dimeric tetraorganostannoxanes are proposed for 1 and 2, and monomeric hexa-coordinate structure for 3, respectively. The crystal structure of 1 was determined by X-ray crystallography. This structure is self-assembled via π → π and C-H → π stacking interactions. Flufenamic acid and flufenamates 2 and 3 were evaluated for antiproliferative activity in vitro. Among the compounds tested 2 and 3 exhibited high cytotoxic activity against the cancer cell line A549 (non-small cell lung carcinoma).