One‐Pot Synthesis of 2‐Amino‐6‐(1,2‐dihydro‐4‐hydroxy‐2‐oxoquinolin‐3‐yl)‐4‐arylpyridine‐3‐carbonitriles Catalysed by NbCl₅ and Their In Vitro Antimicrobial Studies

Abstract

Synthesis of 2-amino-6-(1, 2-dihydro-4-hydroxy-2-oxoquinolin-3-yl)-4-arylpyridine-3-carbonitrile has been accomplished via NbCl 5 catalysed multicomponent reaction (MCR). The tested compounds showed better potency than Neomycin and a broad spectrum of antibacterial activity against Staphylococcus aureus, Bacillus cereus and Escherichia coli. Similarly some of these have showed good activity against Staphylococcus aureus, Klebsiella planticola and Escherichia coli that were comparable to Ciprofloxacin. Also these compounds possess good antifungal activity that was better than Miconazole and comparable to Ciprofloxacin hydrochloride.

Bioactive 2-pyridone-containing heterocycle syntheses using multicomponent reactions

“…For instance, Krishna and colleagues described the synthesis of quinolone–pyridine hybrids 45 in 63–85% yields through a time-efficient four-component reaction of (hetero)aromatic aldehydes 1, malononitrile 2, 3-acetyl-4-hydroxy-2(1 H )-quinolone 44, and an excess of ammonium acetate catalyzed by NbCl 5 (15 mol%) in DMF at 75 °C for 30 min ( Scheme 11 ). 62 The compounds 45a–p were screened for their antibacterial activity against two Gram-positive ( Staphylococcus aureus and Bacillus cereus ) and three Gram-negative ( Klebsiella planticola , Escherichia coli , and Pseudomonas aeruginosa ) bacterial strains using Ciprofloxacin hydrochloride as a standard drug. It was found that compound 45e (R = 4-MeOC 6 H 4 ) exhibited an excellent activity against Staphylococcus aureus and Bacillus cereus with a MIC value of 2.34 μg mL −1 , in comparison to Ciprofloxacin hydrochloride (MIC = 4.68 and 2.34 μg mL −1 , respectively).…”

“…Alternatively, Krishna and colleagues described the synthesis of quinolone–pyridine hybrids 45 via an NbCl 5 -catalyzed four-component reaction and discussed in Section 2.2. Antibacterial activity ( Scheme 11 ), 62 were also screened for their antifungal activity against Candida albicans , Candida parapsilosis , Candida glabrata , Candida aaseri , Aspergillus niger , and Issatchenkia hanoiensis using Miconazole as a standard drug. Particularly, the compound 45n (R = naphthalene-2-yl) showed the highest activity against tested Candida and fungal pathogens with MIC values ranging from 1.67 to 9.37 μg mL −1 , in comparison to Miconazole (MIC = 4.68–9.37 μg mL −1 ).…”

Highlights on quinolonic compounds with changes on the basic structure as promising molecules to new drugs

“…The quinolonic moiety is a pharmacophoric group and it is used for the development of new substances. It is possible find on the literature a wide variety of biological activities (DHIMAN et al, 2019), such as: anticancer (RELITTI et al, 2020;GAO et al, 2019;ZHAO & YU 2018;CHEN et al, 2004), antifungal (KHAMKHENSHORNGPHANUCH et al, 2020ZANG, 2019;EL-DESOKY et al, 2018), antioxidant JAYASHREE et al, 2010;CHUNG & WOO, 2001), antimalarial (BETECK et al, 2019;FAN et al, 2018;WUBE et al, 2014), antibacterial (LI & CLARK, 2020;KOIDE et al, 2019;KRISHNA & SARVESWARI, 2019;VALADBEIGI & GHODSI, 2017;PANDA et al, 2015;KERNS et al, 2003) and antimycobacterial (BETECK et al, 2020;BETECK et al, 2019;HONG et al, 2017;PUCCI et al, 2010) (Figure 2). Source: Adapted from antifungal: ZANG, 2019;antibacterial: PANDA et al, 2015;antioxidant: JAYASHREE et al, 2010.;antimycobacterial:PUCCI et al, 2010;antineoplasic: GAO et al, 2019 antimalarial: WUBE et al, 2014.…”