Nickel Nanoparticles as a Sustainable Catalyst for the Synthesis of 2H-Pyran Derivatives under Microwave Irradiation, and their Anti-Inflammatory Activity

This study includes an environmentally and effectively green method for the synthesis of novel 2H-pyran derivatives 4 a-h via a one-pot reaction of different aromatic aldehydes 1 a-h with ethyl cyanoacetate (2) and 2-acetylphenyl-4-tolylsulfonate (3) in the presence of nickel oxide nanoparticles (NiO NPs) as a green catalyst in an aqueous mixed solution (EtOH: H2O, 1 : 3 ratio) using microwave irradiation. The structure of all prouducts were confirmed by spectral data and elemental analysis. All compounds were investigated for anti-inflammatory activity compared with celecoxib as a reference drug. The obtained results indicate that 2-[4-(4-tosyl oxy phenyl)-3-cyano-2-oxo-2H-pyran-6-yl]phenyl 4-tolylsulfonate (4 b) is the most anti-inflammatory effective, which showed after 5 h., significantly inhibited inflammation compared with the carrageenan alone group (P < 0.0001)., and when compared to the treated group with celecoxib, inflammation was inhibited 42.38 % for compound 4 b compared to celecoxib 48.39 % simultaneously. Moreover, its histopathological examination was studied and showed a significant attenuation of inflammation and edema. The results indicated that pyran derivatives could serve as promising lead compounds for further optimization as anti-inflammatory agents. The present protocol offers several advantages, such as inexpensive, easy work, pure products, shorter reaction times, excellent yields, environmental friendliness, and easy reuse of the catalyst several times.