Synthesis and In Vitro Antiprotozoan Evaluation of 4-/8-Aminoquinoline-based Lactams and Tetrazoles

A second generation of 4-aminoquinoline- and 8-aminoquinoline-based tetrazoles and lactams were synthesized via the Staudinger and Ugi multicomponent reactions. These compounds were subsequently evaluated in vitro for their potential antiplasmodium activity against a multidrug-resistant K1 strain and for their antitrypanosomal activity against a cultured T. b. rhodesiense STIB900 strain. Several of these compounds (4a–g) displayed good antiplasmodium activities (IC₅₀ = 0.20–0.62 µM) that were comparable to the reference drugs, while their antitrypanosomal activity was moderate (<20 µM). Compound 4e was 2-fold more active than primaquine and was also the most active (IC₅₀ = 7.01 µM) against T. b. rhodesiense and also exhibited excellent aqueous solubility (>200 µM) at pH 7.     

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.     

Indolizine Studies,Part 5: Indolizine-2-carboxamides as Potential HIV-1 Protease Inhibitors[ 1 ]

1,1-Carbonyldiimidazole-promoted coupling of Baylis–Hillman-derived indolizine-2-carboxylic acids with a range of amine and amino acid derivatives has provided access to the corresponding carboxamides in moderate to excellent yield.