Prospects and Applications of Palladium Nanoparticles in the Cross-coupling of (hetero)aryl Halides and Related Analogues

Discovering efficient methods for the formation of carbon-carbon bonds is a central ongoing theme in organic synthesis. Cross-coupling reactions catalysed by metal nanoparticles are attractive alternatives to the traditional use of metal counterparts due to the catalytic tunability, selectivity, recyclability and reusability of the nanoparticles. The ongoing search for sustainable processes demands that reusable and environmentally benign catalysts are used. While the advantages of nanoparticles catalysts over bulk catalysts cannot be overemphasised, the problem of sintering, agglomeration and leaching are drawbacks to their full industrial applications. Hence, efforts are being made towards advancing the efficiency of the catalytic nanoparticle systems over the years. This review presents the progress, the challenges and the prospects of palladium nanoparticle with focus on Heck, Suzuki, Hiyama and Sonogashira cross-coupling reactions involving (hetero) aryl halides and the analogues.

New sulphonamide pyrolidine carboxamide derivatives: Synthesis, molecular docking, antiplasmodial and antioxidant activities

Carboxamides bearing sulphonamide functionality have been shown to exhibit significant lethal effect on Plasmodium falciparum, the causative agent of human malaria. Here we report the synthesis of thirty-two new drug-like sulphonamide pyrolidine carboxamide derivatives and their antiplasmodial and antioxidant capabilities. In addition, molecular docking was used to check their binding affinities for homology modelled P. falciparum N-myristoyltransferase, a confirmed drug target in the pathogen. Results revealed that sixteen new derivatives killed the parasite at single-digit micromolar concentration (IC₅₀ = 2.40–8.30 μM) and compounds 10b, 10c, 10d, 10j and 10o scavenged DPPH radicals at IC₅₀s (6.48, 8.49, 3.02, 6.44 and 4.32 μg/mL respectively) comparable with 1.06 μg/mL for ascorbic acid. Compound 10o emerged as the most active of the derivatives to bind to the PfNMT with theoretical inhibition constant (K_i = 0.09 μM) comparable to the reference ligand pyrazole-sulphonamide (K_i = 0.01 μM). This study identifies compound 10o, and this series in general, as potential antimalarial candidate with antioxidant activity which requires further attention to optimise activity.

Synthesis, molecular docking, antiplasmodial and antioxidant activities of new sulfonamido-pepetide derivatives

Twenty-three new series of toluene-sulfonamide dipeptide derivatives were synthesized and screened for antiplasmodial and antioxidant potencies. Many of the derivatives were active against Plasmodium falciparum with IC50 ranging from 3.20 - 9.10 μM. The ability of compounds 7h, 7m and 7n (IC50 of 7.53, 7.21 and 6.01 μg/mL respectively) to scavenge DPPH free radicals were comparable to that of ascorbic acid. Additionally, molecular docking disclosed that four compounds exhibited theoretical inhibition constant at submicromolar concentrations (K i = 0.72, 0.75, 0.57, and 0.53 μM respectively) compare to the reference ligand (a pyrazole sulfonamide; K i = 0.01 μM). Overall, some of the derivatives possess antimalarial property as well as the ability to inhibit oxidative stress in malaria pathophysiology; and hence, are good candidates for further antimalarial drug research.

Recent advances in transition metal-catalysed cross-coupling of (hetero)aryl halides and analogues under ligand-free conditions

The formation of new bonds is pivotal in organic chemistry and a prerequisite to life because it allows the construction of complex molecules from simple precursors.