Exploration of catalytic activity of newly developed Pd/KLR and Pd-Cu/KLR nanocomposites (NCs) for synthesis of biologically active novel heterocycles via Suzuki cross-coupling reaction
Neetu Yaduvanshi, Meenu Devi, Sanjana Tewari, Shivangi Jaiswal, S. Z. Hashmi, Shruti Shukla̽, Jaya Dwivedi, Swapnil Sharma
Abstract
The present articles aimed at the synthesis of biologically active novel heterocycles via selective construction of C C bond through a cross-coupling reaction between a heterocyclic aryl halide and phenylboronic acid catalyzed by the newly developed Pd-KLR (Palladium-Kaphal leaves residue) and Pd-Cu-KLR nanocomposites (NCs). The biological properties of the newly synthesized heterocycles were examined using molecular docking studies. Pd-KLR nanocomposites (NPs) and Pd-Cu/KLR nanoparticles (NCs) were synthesized using kaphal (box berry) leaves extract, the extracted residue of kaphal leaves is used as a carrier and reducing agent in the cross-coupling reaction. The synthesized Pd NCs and Pd-Cu NPs were characterized using FT-IR, UV-visible, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. Molecular docking results revealed that the newly synthesized heterocycles exhibit impressive affinity towards bacterial topoisomerase II that indicated their antibacterial properties. The cluster Pd-KLR NCs and spherical Pd-Cu-KLR NPs had a mean particle size of around 110 nm and 53 nm. The comparative study of both Pd-KLR and Pd-Cu-KLR nanocatalysts is studied. However, the heterogeneous Pd-KLR nanocomposite showed excellent catalytic activity for the heterocyclic Suzuki Cross-Coupling reaction. The yield of the reaction of 3-amino-2-chloropyridine with phenylboronic acid using EtOH solvent in the presence of NaOH base and a very little amount of Pd 0.02 /KLR (0.1 mmol%) catalyst at 78 °C temperature under microwave irradiations for 10 min is noticed as 96.7%. Furthermore, the catalyst could be recycled for up to seven cycles without any significant activity loss.