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Schiff bases have continued to gain attention as essential building blocks and versatile pharmacophores in drug development and drug-like molecular entities. Thus, the synthesis of Schiff bases was achieved herein via facile acetic acid catalyzed synthetic transformation of chalcones. The targeted Schiff bases and related compounds 2a-m were accessed by the treatment of amines with chalcone 1 which was previously derived through Claisen-Schmidt reaction between benzaldehyde and acetone, at ambient temperature. Structural characterization was achieved via physicochemical properties and the use of IR, UV, 1 H and 13 C NMR which were spectroscopic techniques. The compounds have essential candidature for further study, in biological activity so as to unleash their medicinal potential.

Benzimidazole derivatives are crucial structural heterocyclic motifs found in diverse libraries of biologically active compounds which are therapeutically useful agents in drug discovery and medicinal research. 2-(3,5-Dinitrophenyl) benzimidazole, 1 was synthesized by [4+1]-cycloaddition of o-phenylenediamine with 3,5dinitrobenzoic acid in catalytic amount of NH 4 Cl. Compound 1 was subsequently utilized as precursor which upon reaction with some halogenated molecular entity furnished the targeted N-substituted-2- (3,5-dinitrophenyl) benzimidazole derivatives in improved yields after reaction optimization engagement. The progress of reaction was monitored with TLC and the chemical structures were confirmed by analytical data and spectroscopic means such as UV, IR, mass spectra, 1 H NMR, 13 C NMR and DEPT-135. The titled compounds were screened for their antimicrobial activity alongside with gentamicin standard drug, using agar diffusion method while the minimum inhibitory concentration (MIC) was carried out using serial dilution method. The result showed that the synthetic method used herein was successful for the preparation of the titled benzimidazole motifs in high yields and eco-friendly manner. The compounds showed broad spectrum of activity and most of them competed favourably with gentamicin and they exhibited highly promising antibacterial potential for future drug development. They are good candidates for further studies in term of SAR study and other pharmacological screenings essential in therapeutic research.