An Eco-Friendly Synthesis of Heterocyclic Moieties Condensed with Pyrazole System under Green Conditions and Their Biological Activity

Abstract

The efficient, facile and green synthesis of 4-bromo pyrazolone by using N-bromo saccharine as valuable green reagent encouraged us to prepare some new fused heterocycles as furopyrazole , pyranopyrazole, imidazopyrazole, pyrazolothiazole, pyrazol thiazolopyrimidine, pyrazolothiazine, oxathinopyrazole, pyrazolobenzooxazine, and pyrazoloquinoxaline. The synthesis was carried out by a basic condensation of bromo pyrazolone 2 and a suitable reagent in a one-pot reaction using chitosan as a green basic catalyst. The reactions were carried out by microwave irradiation technique as a green source of energy as well as the conventional heating. The antioxidant activity of the prepared compounds was studied using 1,1-phenyl-2-picrylhydrazyl (DPPH) assay and their antibacterial activity against Gram-positive, Gram-negative bacteria and antifungal activity was evaluated.