Schiff’s base derivatives bearing 2-thiophenoxyquinoline nucleus as new antibacterial agents

Quinoline Hydrazide/Hydrazone Derivatives: Recent Insights on Antibacterial Activity and Mechanism of Action

Antibiotics are becoming gradually ineffective due to drug resistance, leading to greater difficulty in the treatment of infectious diseases. Therefore, the development of new chemical entities with different mechanisms of action is essential in the fight against resistant microorganisms. Various studies have shown that quinoline hydrazide/hydrazone derivatives possess several biological activities, such as antimalarial, antitubercular, anticancer, anti-inflammatory, and antimicrobial. Among these activities, the antibacterial activity of quinoline hydrazide/hydrazone derivatives is noteworthy. The synthetic flexibility of the quinoline ring has led to the development of a wide range of structurally diverse quinoline hydrazide/hydrazone derivatives, which can act at various bacterial targets such as DNA gyrase, glucosamine-6-phosphate synthase, enoyl ACP reductase, and 3-ketoacyl ACP reductase. This review emphasizes the antibacterial potential of various reported quinoline hydrazide/hydrazone derivatives based on substitution in the quinoline ring. The antibacterial activity of various metal-quinoline hydrazide/hydrazone complexes is also discussed. The aim of this review is to assemble and scrutinize the latest reports in this promising area of drug development.

Synthesis of functionalized 3-, 5-, 6- and 8-aminoquinolines via intermediate (3-pyrrolin-1-yl)- and (2-oxopyrrolidin-1-yl)quinolines and evaluation of their antiplasmodial and antifungal activity

(3-Pyrrolin-1-yl)- and (2-oxopyrrolidin-1-yl)quinolines were prepared via cyclization of diallylaminoquinolines and 4-chloro-N-quinolinylbutanamides, respectively, as novel synthetic intermediates en route to N-functionalized 3-, 5-, 6- and 8-aminoquinolines with potential biological activity. (3-Pyrrolin-1-yl)quinolines were subjected to bromination reactions, and the reactivity of (2-oxopyrrolidin-1-yl)quinolines toward lithium aluminum hydride and methyllithium was assessed, providing an entry into a broad range of novel functionalized (pyrrolidin-1-yl)- and (hydroxyalkylamino)quinolines. Antiplasmodial evaluation of these novel quinolines and their functionalized derivatives revealed moderate micromolar potency against a chloroquine-sensitive strain of the malaria parasite Plasmodium falciparum, and the two most potent compounds also showed micromolar activity against a chloroquine-resistant strain of P. falciparum. Antifungal assessment of (hydroxyalkylamino)quinolines revealed three compounds with promising MIC values against Rhodotorula bogoriensis and one compound with potent activity against Aspergillus flavus.