Synthesis of pyridines and pyrazols derivatives using an engineered ionic-liquid-based nanomagnetic catalyst

Abstract

This study focuses on the design and synthesis of a magnetic heterogeneous catalyst using fluorescent carbon quantum dots (CQDs) as a sustainable support material. This approach addresses the challenges associated with the difficult catalyst separation and functionalization of iron oxide nanoparticles. The core–shell support, named Fe₃O₄@CQD@Si(CH₂)₃NH@CC@Ad, was developed to load a maximum amount of acid groups (–SO₃H) onto the support. The core is composed of magnetic Fe₃O₄, while the outer shell is composed of functionalized CQDs. The synthesized catalyst was characterized to confirm its structure and properties. The efficiency of this nanocatalyst was then evaluated in the synthesis of 2-amino-3-cyano pyridines and 4,4′-(aryl methylene) bis(3-methyl-1H-pyrazol-5-ol)s derivatives using a multi-component reaction (MCR). Reactions conducted with the magnetic nanocatalyst under optimized conditions resulted in reasonable yields within a short duration. The authors suggest that the high immobilization of the –SO₃H groups on the Fe₃O₄@CQD@Si(CH₂)₃NH@CC@Ad support was favored by the aggregation of the –NH groups. This aggregation promoted the catalytic efficiency and activity of the catalyst by increasing the availability of acidic active sites. The overall results indicate that the designed catalyst maintains a relatively high level of efficiency even after several cycles of use. This robustness and the sustained catalytic activity highlight the catalyst’s potential for practical applications in various industrial processes.

Graphic Abstract