Rational design, synthesis and biological evaluation of thiadiazinoacridines: A new class of antitumor agents Original Research Article

A series of potential DNA-binding antitumor agents, 3-[ω-(alkylamino)alkyl]-6-nitro-thiadiazino[3,4,5-kl]acridines 12 and 1,3-di[ω-(alkylamino)alkyl]-6-nitro-thiadiazino[3,4,5-kl]acridines 13, has been prepared by cyclization with SOCl2 of 1-{[ω-(alkylamino)alkyl]amino}-9-imino-4-nitro-9,10-dihydroacridines 16 or 1-{[ω-(alkylamino)alkyl]amino}-9-[ω-(alkylamino)alkyl]imino-4-nitro-9,10-dihydroacridines 17, respectively. The non-covalent DNA-binding properties of 12, 13 have been examined using a fluorometric technique. In vitro cytotoxic potencies of these derivatives toward six tumor cell lines, including human colon adenocarcinoma (HT29) and human ovarian carcinoma (A2780 sensitive, A2780cisR cisplatin-resistant, CH1, CH1cisR cisplatin-resistant, and SKOV-3) cells, are described and compared to that of reference drugs. In vivo antitumor activity of some selected derivatives, endowed with relevant cytotoxic activity against murine leukemia P388 are reported. The 3-[2-(dimethylamino)ethyl]-6-nitro-2,7-dihydro-3H-2λ4-thiadiazino[3,4,5-kl]acridin-2-one (12d) has been identified as a new lead in the development of anticancer tetracyclic acridine derivatives.