A series of novel substituted benzimidazole (7a -n) derivatives were synthesized and characterized by 1 H, 13 C Nuclear Magnetic Resonance (NMR) spectra and High Resolution Mass Spectrometry (HRMS). The substitution was done in position -1 and -2 by appropriate groups. These compounds are obtained by N-alkylation reaction with thiomethyl-1H-benzimidazole intermediates (5a -g). Design of intermediates (5a -g) was made by condensation reaction between 2-methylbenzimidazole thiourunium salt (3) and functionalized halides (4) in the presence of sodium hydroxide (NaOH). Among the twenty-one compounds synthesized, ten were evaluated for their antimicrobial activity on three bacterial strains namely: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853. Only E. coli ATTC 25922 was susceptible to the synthesized derivatives 5g, 7f and 7h with a significant antibacterial activity (CMI is between 250 and 500 μg/mL).

N-Heterocyclic scaffolds have generated significant interest among medicinal chemists. Among these potential heterocyclic drugs, benzimidazole and imidazopyridine scaffolds are the most prevalent. Over the past few decades, it has gained immense attention. Both are important classes of molecules owing to their wide spectrum of biological activities and clinical applications. Both are used in fashion design and the development of novel synthetic analogs for various therapeutic disorders. A wide variety of derivatives have been developed as potential anticancer, antimicrobial, antiviral, and anti-inflammatory agents in addition to other chemotherapeutic agents. The benzimidazole core is found in a natural system, displaying a wide range of pharmaceutical properties, and has gained significant attention in medicinal chemistry, as reported in several full articles and communications. Imidazopyridines are widely distributed in many pharmacologically important compounds, as shown by their frequent occurrence in a large number of marketed drug formulations and drug candidates, as well as in other fields such as material and organometallic chemistry. These scaffolds have been structurally characterized as ligands that can bind to different receptor sites for the discovery of various emerging drugs. They act as key pharmacophore motifs for the identification and optimization of lead structures to increase the medicinal chemistry toolbox. This review outlines the synthesis and medicinal significance of benzimidazoles and imidazopyridines for their development as lead molecules with improved therapeutic efficiency. Here, we cover the various designs used to obtain both heterocycles to establish a relationship between their combination and biological activities.

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The N heterocyclic scaffold has generated a lot of interest among medicinal chemists. Of those potential heterocyclic drugs, benzimidazole and imidazopyridine scaffolds are considerably prevalent. They have gained tremendous importance over the past few decades. Both are an important class of molecules due to their wide spectrum of biological activities and clinical applications. Both are used in fashion design and the development of novel synthetic analogs for various therapeutic disorders. A wide variety of their derivatives have been developed as potential anti-cancer, anti-microbial, anti-viral, and anti-inflammatory besides other chemotherapeutic agents. Benzimidazole core was found in the natural system displaying a wide range of pharmaceutical properties and it gained significant attention in medicinal chemistry reported in several full articles and communications. While imidazopyridines exhibit a vast distribution in many pharmacologically important compounds shown by its frequent occurrence in a large number of marketed drug formulations and drug candidates as well as in other fields such as material and organometallic chemistry. These scaffolds are characterized as structurally potential ligands which can bind to different receptor sites for the discovery of various immerging drugs. They act as key pharmacophore motifs for the identification and optimization of lead structures to increase the medicinal chemistry toolbox. The present review outlines the synthesis and the medicinal significance of benzimidazoles and imidazopyridines for their development as lead molecules with improved therapeutic efficiencies. Here, we cover the various design used to obtain both heterocycles to establish a relationship between their combination to features the biological activities.

In pursuit the development of novel potent and selective antibacterial agents, we synthesized twelve (12) N-alkyl 2-benzylthiomethyl-1H-benzimidazole derivatives and evaluated their antibacterial activities. Their antibacterial profile was determined with minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) against a small set of two (2) strains Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive). These compounds are produced by the condensation reaction of 2-benzylthiomethyl-1H-benzimidazole (5) with benzyl chloride or bromide (6) in the presence of potassium carbonate (K2CO3). The panel of twelve synthetized compounds (7a-l) were characterized by NMR 1H, 13C spectroscopy, and high-resolution mass spectrometry (HRMS). The results showed that compounds 7a, 7b, 7c, 7d, 7e, 7f, 7h, 7k, and 7l were potent against Escherichia coli and Staphylococcus aureus, with significant MICs values from 140 to 290 µg/mL. On E. coli, five (5) compounds 7b, 7f, 7i, 7k and 7l showed bactericidal effects within common an N-alkylation by R3= phenyl, methyl, and CH2OH on the benzimidazole scaffold and the benzylthiol substituted by R2= Cl or CF3. This is evidence or a probe of these chemical groups implementing the bactericidal activity.

Eighteen new N‐acylhydrazones (9a–r) containing the imidazo[1,2‐a]pyridine scaffold were synthesized through a seven steps reaction sequence, ending with a condensation of 2‐(3‐nitro‐H‐imidazo[1,2‐a]pyridin‐2‐ylthio)acetohydrazide with various benzaldehyde derivatives (8a–r). All synthesized compounds were characterized by 1D NMR (1H and 13C NMR) and 2D NMR (NOESY) spectroscopic analyses and high‐resolution mass spectrometry (HRMS). The analysis of 1H NMR data performed at room temperature in deuterated dimethylsulfoxide (DMSO‐d6) revealed the presence of (E)‐2‐(3‐nitro‐H‐imidazo[1,2‐a]pyridin‐2‐ylthio)‐N′‐benzylideneacetohydrazide (9a–r) as a mixture of two conformers, namely, syn‐periplanar E (sp E) and anti‐periplanar E (ap E). For all N‐acylhydrazones that were synthesized, the sp E conformer was found to be the major form except in the case of hydrazone derived from o‐hydroxybenzaldehyde.

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