Synthesis and Antimicrobial Activity of 4-Substituted 1,2,3-Triazole-Coumarin Derivatives

Abstract

A new series of coumarin-1,2,3-triazole conjugates with varied alkyl, phenyl and heterocycle moieties at C-4 of the triazole nucleus were synthesized using a copper(I)-catalysed Huisgen 1,3-dipolar cycloaddition reaction of corresponding O-propargylated coumarin (3) or N-propargylated coumarin (6) with alkyl or aryl azides. Based on their minimal inhibitory concentrations (MICs) against selected microorganisms, six out of twenty-six compounds showed significant antibacterial activity towards Enterococcus faecalis (MIC = 12.5–50 µg/mL). Moreover, the synthesized triazoles show relatively low toxicity against human erythrocytes.

Role of Herbs and Medicinal Spices as Modulators of Gut Microbiota

“…Many coumarins are synthesized in the lab and used as medicines for humans and animals. In this sense, coumarin-1,2,3triazole conjugate and 3-heteroarylazo 4-hydroxy showed bactericidal action against Enterococcus faecalis [80] and Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa [69], respectively ( Table 1).…”

Coumarin‐containing hybrids and their antibacterial activities

“…Replacement of the ether linker between coumarin and 1,2,3‐triazole moieties by amino linker was harmful to the activity, as evidenced by hybrids 3 (MIC: 50–1,600 µg/ml) that only showed weak‐to‐moderate activity against S. aureus , Enterococcus faecalis ( E. faecalis ), E. coli , Klebsiella pneumonia ( K. pneumonia ), and Pseudomonas aeruginosa ( P. aeruginosa ), implying that the oxygen was critical for the high activity. [ 42 ] The movement of 1,2,3‐triazole fragment from C‐7 position of coumarin moiety to C‐6 position was also tolerated, and hybrids 4a,b (inhibition zone: 23 and 30 mm at 50 µg/ml) exhibited potential activity against S. aureus and E. coli . [ 43 ] Particularly, hybrids 1a (MIC: 2–16 µg/ml) and 2a (MIC: 2–8 µg/ml) were comparable to the references ampicillin, kanamycin, and chloramphenicol (MIC: 2–16 µg/ml) against the six tested bacteria, [ 41 ] implying the potential applicability of these hybrids as antibacterial agents.…”

Recent updates of fluoroquinolones as antibacterial agents

“…The 1,2,3‐triazole hybrides containing aryl group, compounds 34 – 36 showed promising antibacterial properties against the tested Gram‐positive bacteria ( S. aureus and Streptococcus pyogenes ) with potency higher than that of the parent antibiotics (ciprofloxacin, norfloxacin, and pipemidic acid) with MIC values of 0.2–0.5 μg/mL . Also compounds 34–36 revealed remarkable antibacterial properties against the Gram‐negative Salmonella typhi and E. coli with MIC values of 0.2–0.5 μg/mL .…”