Synthesis, characterization and antimicrobial studies of some new quinoline incorporated benzimidazole derivatives

Design, Synthesis and Antibacterial Evaluation of Some New 2-Phenyl-quinoline-4-carboxylic Acid Derivatives

“…The intermediate 2-(2-nitrophenyl)-quinoline-4-carboxylic acid (1) is considered to be a category of versatile intermediates that provide building blocks in the synthesis of poly-substituted quinoline-4-carboxylic acid derivatives. Several methods have been developed to date for the synthesis of 2-(2-nitrophenyl)-quinoline-4-carboxylic acid, and these include the Doebner reaction using aniline, 2-nitrobenzaldehyde, pyruvic acid and a catalytic amount of trifluoroacetic acid in ethanol media [14,15], as well as the versatile Pfitzinger reaction by reacting isatin with α-methyl ketone in aqueous ethanol [22,30,31]. 2-(2-nitrophenyl)-quinoline-4-carboxylic acid was also prepared via Doebner reaction under microwave [25,26,32,33].…”

“…Some quinoline-4-carboxylic acid derivatives exhibited certain antibacterial activity [20,21]. Furthermore, a literature review revealed that the presence of an aryl ring at the second position of quinoline-4-carboxylic acid derivatives exhibits good antibacterial activity for the target compound and plays a significant role in the development of new antibacterials (Figure 1) [6,15,[22][23][24][25][26][27], and they are very suitable for further modifications to obtain more effective antibacterial agents. In addition, the structure-activity relationship (SAR) studies of quinolones have indicated that the introduction of a basic group in the quinoline is useful for regulating the physicochemical property and influencing their potency, spectrum and safety [28,29].…”

“…The quinoline ring occurs in various natural products and represents a key motif in medicinal chemistry [9][10][11][12], and its derivatives, quinoline-4-carboxylic acids, are a group of compounds associated with different biological activities, such asantiviral [13], anti-inflammatory [14], antimicrobial [15], anti-atherothrombosis [16], antiemetic [17], anxiolytic [18], antimalarial and antileishmanial [19]. Although quinoline-4-carboxylic acid derivatives exhibit various bioactivities, the research of new quinoline-4-carboxylic acid-based antibacterial drugs has developed slowly.…”

Structure activity relationship (SAR) study of benzimidazole scaffold for different biological activities: A mini-review

“…Among the screened compounds 38a, 38b, 39a and 39b showed excellent inhibition of bacterial growth. Compound 39b showed significant inhibition of fungal strain [66].SAR study is demonstrated in Fig.27. Seenaiah et al reported some benzimidazole derivatives bearing thio, methylthio and amino moieties as antimicrobials.Compound 42 surfaced out as the most potent antimicrobial against Staphylococcus aureus (29 mm and 12.5µM) and Penicillium chrysogenum (38 mm and 12.5µM) on evaluation with the parameters of zone of inhibition and MIC values.…”

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“…In recent years, the mounting threat of bacterial resistance has heightened the urgency to discover and develop anti-infective agents with novel mechanism of action and enhanced activity profile [1]. Clinical use of potent drugs is limited in many cases due to their side effects.…”