New thiazolidine-2,4-dione derivatives combined with organometallic ferrocene: Synthesis, structure and antiparasitic activity

Favourable physicochemical properties of an organometallic ferrocene and antiplasmodial potency of compounds containing the thiazolidine-2,4-dione framework (TZD-4) prompted us to explore compounds containing both the thiazolidine-2,4-dione core and the ferrocenyl unit with the primary aim of identifying compounds with promising antiprotozoal activities. Thus, a new series of rationally designed ferrocene-based thiazolidine-2,4-dione derivatives, containing a selection of secondary cyclic amines, was synthesised and fully characterised using standard spectroscopic techniques. The resulting compounds were screened for their antiplasmodial and antitrypanosomal activities against both the chloroquine-resistant (Dd2) strain of Plasmodium falciparum and the Nagana Trypanosoma brucei brucei 427. The general trend that emerged indicated that the target compounds were more selective towards T. b. brucei compared to the P. falciparum parasite. Moreover, the analogues bearing methylpiperazine (8a) and piperidine (8b) rings were more active against T. b. brucei compared to hit compound TZD-4. Except compound 8b, which appeared promising, none of the synthesised compounds showed better activity than TZD-4 against the P. falciparum parasite. All the synthesised compounds were non-toxic and often showed >90% viability of the HeLa cell line screened.