A Palladium Catalyst System for the Efficient Cross-Coupling Reaction of Aryl Bromides and Chlorides with Phenylboronic Acid: Synthesis and Biological Activity Evaluation.

Boubakri Lamia,Naceur Hamdi,Lamjed Mansour,Ismail Özdemir,Sedat Yaşar,Bilel Hallouma,Ahlem Chakchouk-Mtibaa,Lotfi Mellouli

doi:10.3390/molecules22030420

Abstract

New benzimidazolium salts 1a–c and their palladium bis-N-heterocyclic carbene complexes 2a–c and palladium PEPPSI-type complexes 3a–c were designed, synthesized and structurally characterized by NMR (1H and 13C), IR, DART-TOF mass spectrometry and elemental analysis. Then these complexes 2–3 were employed in the Suzuki-Miyaura cross-coupling reaction of substituted arenes with phenylboronic acid under mild conditions in toluene and DMF/H2O (1/1) to afford functionalized biaryl derivatives in good to excellent yields. The antibacterial activity of palladium bis-N-heterocyclic carbene complexes 2a–c and palladium PEPPSI-type complexes 3a–c was measured by disc diffusion method against Gram positive and Gram negative bacteria. Compounds 2a, 2c and 3a–c exhibited potential antibacterial activity against four bacterial species among the five used indicator cells. The product 2b inhibits the growth of the all five tested microorganisms. Moreover, the antioxidant activity determination of these complexes 2–3, using 2.2-diphenyl-1-picrylhydrazyl (DPPH) as a reagent, showed that compounds 2a–c and 3b possess DPPH antiradical activity. The higher antioxidant activity was obtained from the product 2b which has radical scavenging activity comparable to that of the two used positive controls (gallic acid “GA“ and tutylatedhydroxytoluene “BHT“). Investigation of the anti-acetylcholinesterase activity of the studied complexes showed that compounds 2b, 3a, and 3b exhibited moderate activity at 100 μg/mL and product 2b is the most active.

Highlights

N-heterocyclic carbene (NHC) ligands have become ubiquitous in the preparation of metal complexes with new catalytic applications
In an attempt to provide a new vision of the topic, this article will focus our attention on the development of new palladium complexes with NHC ligands, paying special attention to their applications in catalytic processes other than the classical C-C coupling [1,2,3,4]
In present study, we investigated whether the palladium bis-N-heterocyclic carbene complexes 2a–c and palladium PEPPSI-type complexes 3a–c could serve as a potent antioxidant

Summary

Introduction

N-heterocyclic carbene (NHC) ligands have become ubiquitous in the preparation of metal complexes with new catalytic applications. Due to their applications in C-C bond formation. In an attempt to provide a new vision of the topic, this article will focus our attention on the development of new palladium complexes with NHC ligands, paying special attention to their applications in catalytic processes other than the classical C-C coupling [1,2,3,4]. Sonogashira reactions of with NHC ligands, paying special attention to their applications in catalytic processes other than the unactivated alkylC-C bromides classical coupling[11]

Methods

Findings

Discussion

Conclusion