Nickel(II) Chromite Nanoparticles: An Eco-Friendly and Reusable Catalyst for Synthesis of 2,4-Diamino-6-aryl-pyrimidine-5-yl Cyanides under Ultrasonic Radiation

Abstract

Background: One of the principal factors in the field of research in green chemistry is to drive chemical reactions under ultrasonication as a versatile synthetic tool. Moreover, nanostructured metal salts occupy an important position as low cost, efficient, heterogeneous, and green catalysts in chemical reactions. Pyrimidine has also acquired significance because it is a core structure in a variety of natural and non-natural agents, many of which display versatile biological activities and medical applications. Objective: The aim of this study was to explore the role of nickel(II) chromite nanoparticles (NiCr2O4 NPs) as a green and recyclable catalyst for the synthesis of 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides under ultrasonic radiation. Methods: A direct cyclocondensation reaction of guanidine nitrate, aromatic aldehydes, and malononitrile were performed using NiCr2O4 NPs as an effective heterogeneous catalyst under ultrasonic radiation at room temperature conditions to prepare 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides in high yields. The described catalyst was prepared successfully according to a simple hydrothermal route and fully characterized by the X-Ray diffraction (XRD) technique, energy dispersive X-Ray (EDS) analysis, scanning electron microscopy (SEM), and dynamic light scattering (DLS). Results: A number of 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides were effectively synthesized in high yields (94-98%) within short reaction times (15 min). All synthesized compounds were well characterized by IR, 1H and 13C NMR spectroscopy, and also by elemental analyses. Conclusion: In conclusion, a simple, efficient, and green synthesis of 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides was developed using NiCr2O4 NPs as green nanocatalyst, and under ultrasound radiation as green tool. The mild reaction conditions, avoiding the use of toxic solvents or reagents, high atom economy, high yields, and simple work-up are the attractive features of this new protocol.

Sustainable synthesis of [1]benzopyran azo dyes using CuCr2O4 NPs

“…As plenty, previous research studies have revealed the nanostructured metal solids are increasingly popular as valuable and advantageous catalysts in various chemical reactions. Among various inorganic solids, spinel type metal chromite with the general formula AB 2 O 4 with high efficiency, nontoxicity, good stability, low-cost synthesis, and recyclability can be considered suitable heterogeneous catalysts for organic transformations [15][16][17][18][19][20][21].…”