Success of the cisplatin paved the way for second and third generation platinum drugs such as carboplatin, oxaliplatin. However, novel platinum agents still appeal much attention for the reason that drug resistance and several disadvantages, particularly related to general toxicity which lead to undesirable side effects are often detected with the current Pt based drugs.
Benzothiazole aniline (BTA) is a potent and selective antitumor agent, displayed characteristic profile of cytotoxic response towards various tumor cell lines, whereas no hormonal dependency was identified. Since 1996 a series of benzothiazole derivatives based on the core compound benzothiazole aniline (BTA) have been established as anticancer agents. Also, ring-substituted derivatives of benzothiazole aniline was developed as antitumor agent and one derivative phortress (NSC 710305) was approved for phase 1 clinical trials as the prodrug.
One approach to design novel Pt complexes to attach the platinum coordination moiety with an appropriate carrier ligand which selectively target the cancer cells. Based on the above approach, we design novel ligands L1, L2, L3 and their platinum complexes PtL1, PtL2, PtL3 by conjugate BTA moiety with three different type of Pt (II) coordination cage via amide bond to generate complexes with two active sites on the metal core. (Figure 1)
Here in we report, the synthesis, structural characterization and in vitro cytotoxicity of this novel BTA derivatives and their platinum complexes to use as selective anticancer agents. We hypothesize that, tumor selectivity of this novel compounds were mainly driven by the lipophilic nature of BTA. Except PtL3 all other compounds show higher cytotoxicity than commercially available platinum drug cisplatin.