C. P. Kaushik

Synthesis and biological evaluation of amino acid-linked 1,2,3-bistriazole conjugates as potential antimicrobial agents

A small library of amino acid-linked 1,4-disubstituted 1,2,3-bistriazole conjugates has been synthesized from the N-protected l-amino acids propargyl esters through one-pot click reaction. All the newly synthesized compounds were tested in vitro for antimicrobial activity against Gram-positive (Staphylococcus aureus, Bacillus subtilis), Gram-negative (Escherichia coli) bacteria and fungi (Candida albicans, Aspergillus niger). The antibacterial evaluation data indicated that compounds 3c, 3h, 5a, 5b, 5c, 5d, 5e, 5g, and 5h exhibited comparable activity to standard ciprofloxacin. However, the bistriazoles 3b, 3c, 3e, 3f, and 3g showed good antifungal activity than others against both fungi. Further, docking simulation of the two most active compounds 5c against S. aureus tyrosyl tRNA synthetase and 5h into E. coli topoisomerase II DNA Gyrase B, respectively, was also performed.

One-pot synthesis and cytotoxic evaluation of amide-linked 1,4-disubstituted 1,2,3-bistriazoles

A series of amide-linked 1,4-disubstituted 1,2,3-bistriazoles have been synthesized employing copper(I)-catalyzed azide–alkyne cycloaddition reaction. All the newly synthesized compounds were screened for in vitro cytotoxicity against a panel of five human cancer cell lines; Fibrosarcoma (HT-1080), Colon (colo205, HCT-116), and Lung (A549, NCIH322). Some of the bistriazoles exhibited moderate to good activity. Compounds 3n and 3o were found to be the more active and displayed broad spectrum activity against all the cancer cell lines under investigation. Further, to study the binding modes for the two more potent compounds 3n and 3o against Human topoisomerase II, docking simulations have been carried out.

Regioselective synthesis and antimicrobial studies of ester linked 1,4-disubstituted 1,2,3-bistriazoles

A series of 1,4-disubstituted 1,2,3-bistriazoles was synthesized via click chemistry by cycloaddition of various bisalkynes with benzyl/2-phenylethyl azide. Synthesized triazoles were characterized by IR, (1)H NMR, (13)C NMR and mass spectral techniques. All the compounds were evaluated for antibacterial/antifungal activities and found to possess moderate to good antimicrobial activities. Further the docking study for the most active compound against DNA Gyrase was also carried out.

Synthesis and antimicrobial evaluation of 1,4-disubstituted 1,2,3-triazoles containing benzofused N-heteroaromatic moieties

Synthesis of a small library of 1,4-disubstituted 1,2,3-triazoles containing benzofused N-heteroaromatic moieties was carried out through click reaction of various benzofused N-heteroaromatic alkynes with aromatic azides. All the synthesized compounds were characterized by spectroscopic techniques like IR, 1H NMR, 13C NMR, mass spectrometry and evaluated in vitro for antimicrobial activity against two Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus), one Gram-negative bacteria (Escherichia coli) and two fungi (Candida albicans, Aspergillus niger). Most of the synthesized 1,4-disubstituted 1,2,3-triazoles were found to possess significant antibacterial and antifungal activity against tested microbial species. Moreover, docking simulation of the compound 1-[(1-(4-nitrobenzyl)-1H-1,2,3-triazol-4-yl)methyl]-1H-benzo[d]imidazole was also carried out against E. coli topoisomerase II DNA gyrase B enzyme to study the binding modes and mechanism of action.Graphical abstract

Synthesis, Characterization, and Antimicrobial Potential of Some 1,4-Disubstituted 1,2,3-Bistriazoles

Abstract A convenient synthesis of some new 1,4-disubstituted 1,2,3-bistriazoles (3a–3f, 4a–4f, 6a–6b, 7a–7b) is reported via copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of various terminal alkynes with 1,4-bis(azidomethyl)benzene and 1,6-diazidohexane. The synthesized compounds were characterized by spectral techniques including infrared, 1H NMR, 13C NMR, and high-resolution mass spectrometry and tested in vitro for antimicrobial potential against Bacillus subtilis and Staphylococcus aureus (Gram-positive bacteria), Pseudomonas aeruginosa and Escherichia coli (Gram-negative bacteria), and Candida albicans and Aspergillus niger (fungi). Among the synthesized 1,4-disubstituted 1,2,3-bistriazoles, compounds 6a, 6b, and 7b displayed excellent antimicrobial potential against most of the tested strains. GRAPHICAL ABSTRACT

Synthesis, antimicrobial activity, and QSAR studies of amide-ester linked 1,4-disubstituted 1,2,3-triazoles

Synthesis of some amide-ester linked 1,4-disubstituted 1,2,3-triazoles was carried out by employing copper(I)-catalyzed 1,3-dipolar cycloaddition of 2-azido-N-substituted acetamides and benzoic acid prop-2-ynyl esters. All the synthesized 28 1,4-disubstituted 1,2,3-triazoles are new. The synthesized triazoles were characterized by IR, 1H NMR, 13C NMR, HRMS and evaluated for their antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans, and Aspergillus niger. Compounds displaying potent antimicrobial activity against each of these microorganisms were found. Quantitative structure activity relationship studies for the synthesized compounds were also carried out to check the effect of various substituents in parent compound on antimicrobial activity.Graphical abstract

Antimicrobial evaluation, QSAR and docking studies of amide-linked 1,4-disubstituted 1,2,3-bistriazoles

Abstract A series of amide-linked 1,4-disubstituted 1,2,3-bistriazoles was tested for antimicrobial activity against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, Gram-negative bacteria Escherichia coli and two fungal strains Aspergillus niger and Candida albicans. The antimicrobial evaluation data indicated that most of the compounds exhibited potential activity. To describe activity on the structural basis, QSAR studies were performed and statistically significant models were developed. Further, binding interactions of two active compounds 17 and 10 to active sites of E. coli topoisomerase II DNA gyrase B and C. albicans lanosterol 14α-demethylase (1.14.13.70) (CYPLI) (cytochrome P450 51) enzymes, respectively, were also examined.

Regioselective synthesis and antimicrobial evaluation of some thioether–amide linked 1,4-disubstituted 1,2,3-triazoles

ABSTRACT A series of 1,4-disubstituted 1,2,3-triazoles having thioether as well as amide linkage were synthesized from aryl(prop-2-yn-1-yl)sulfanes and 2-azido-N-substituted acetamides through Cu(I) catalyzed click reaction. Structures of newly synthesized compounds (3a–3x) were confirmed by spectral techniques like FTIR, 1H NMR, 13C NMR, and HRMS. The synthesized triazoles were evaluated for in vitro antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Candida albicans, and Aspergillus niger. Compounds 3m and 3q displayed appreciable broad spectrum antimicrobial activity against tested microbial strains. The nanoformulations of compounds 3m and 3q were also prepared and examined against one bacterial strain and one fungal strain. GRAPHICAL ABSTRACT

Synthesis and antimicrobial evaluation of ester-linked 1,4-disubstituted 1,2,3-triazoles with a furyl/thienyl moiety

Twenty ester-linked 1,4-disubstituted 1,2,3-triazoles having a furyl/thienyl moiety have been synthesized from heteroaryl prop-2-yn-1-yl carboxylate and aromatic azides via a Cu(I) catalyzed 1,3-dipolar cycloaddition. All the synthesized compounds were characterized by FTIR,