Green routes for the synthesis of new pyrazole bearing biologically active imidiazolyl, pyridine and quinoxaline derivatives as promising antimicrobial and antioxidant agents

In an effort to discover new imidazolyl nucleus belonging to the family of N-fused heterocyclic compounds which display broad spectrum of biological applications, a series of novel imidazolyl pyrazolopyridines 3a,b–7a,b and imidazolyl pyrazoloquinoxaline 8a–d were synthesized. The structures of all the synthesized compounds were confirmed using spectroscopic data and elemental analyses. The compounds were synthesized using conventional heating besides the environmentally friendly benign techniques and reagents as microwave technique and catalyst under solvent–free conditions and short reaction times by anomeric-based oxidation (ABO) to the products in the final step of the synthetic pathway. Further all the synthesized bioactive molecules are tested for their biological potency: in vitro antimicrobial activity using a disc diffusion technique was performed against various Gram-positive and Gram-negative bacteria as well as fungal strains using Chloramophenicol and Fluconazole as positive controls. Free radical scavenging activity has been investigated using the DPPH scavenging methods. Interestingly, most of the synthesized compounds exhibited good to excellent antibacterial activities against most of bacterial strains and showed the highest antioxidant activity.