Synthesis and Antimicrobial Evaluation of Benzimidazolyl pyrimido [4,5-b]quinolinones

2020 ◽  
Vol 17 ◽  
Author(s):  
Gumpula Prasoona ◽  
Baireddy Kishore ◽  
Gavaji Brahmeshwari

Background: As infectious diseases causing bacteria and fungi are developing resistance to existing antimicrobial drugs, it is necessary to search for new drug targets with different structures and mode of action. Hence, it is essential to screen for new antimicrobial drugs with good efficacy and less toxicity. Methods: The reaction of 2-amino benzimidazoles 1 with ethyl cyanoacetate 2 afforded N-(1H-benzo[d]imidazol-2-yl)-2- cyanoacetamides 3. Compounds 3 on Knoevenagel condensation with o-nitro benzaldehydes 4 produced (E)-N-(1Hbenzo[d]imidazol-2-yl)-2-cyano-3-(2-nitrophenol) acylamides 5. Compounds 5 were converted to 2-amino –N-(1Hbenzo[d]imidazol-2-yl) quinoline-3-carboxamides 6 on treatment with stannous chloride by reductive cyclization. The target compounds viz., 3-(1H-benzo[d]imidazol-2-yl)-2-methylpyrimido [4, 5-b] quinolin-4(3H)-ones 7 were obtained by N-acetylation followed by cyclodehydration of compounds 6 in situ by treatment with acetic anhydride. Results: 3-(1H-Benzo[d]imidazol-2-yl)-2-methylpyrimido [4, 5-b] quinolin-4(3H)-ones 7 have been synthesized from commercially available materials in excellent yields. The title compounds 7a-h are evaluated for in vitro antimicrobial activity. Compounds 7e, 7f and 7h have shown more antimicrobial activity than that of standard drugs. Conclusion: The structures of all the newly synthesized compounds 3, 5, 6 & 7 are confirmed on the basis of spectral data. Antimicrobial studies of compounds 7a-h have revealed that compounds 7e and 7f have more efficient activity when compared to the standard drugs.

2018 ◽  
Vol 18 (17) ◽  
pp. 1506-1513 ◽  
Author(s):  
Kashmiri Lal ◽  
Lokesh Kumar ◽  
Ashwani Kumar ◽  
Anil Kumar

Background: Oxazolones and 1,2,3-triazoles are among the extensively studied heterocycles in medicinal chemistry. Both of these moieties are reported to possess a broad spectrum of biological activity including antimicrobial. Objective: The objective of the current work is to design, synthesize and antimicrobial evaluation of some new oxazolone-1,2,3-triazole hybrids. Methods: The designed oxazolone-1,2,3-triazole hybrids were synthesized using copper(I)-catalyzed azide-alkyne cycloaddition. The antimicrobial evaluation was carried out using serial dilution method. Results: Most of the synthesized hybrids showed significant antimicrobial properties. Some of the compounds were found to be possessing better or comparable activity to that of the standards used. The docking simulations results are also in agreement with the antimicrobial activity data. Conclusion: Sixteen new hybrids were synthesized and tested in vitro for their antimicrobial activity. Some of the tested compounds exhibited promising antimicrobial activity and could be utilized for the development of the lead compounds for new and more potent antimicrobial drugs.


2018 ◽  
Vol 15 (8) ◽  
pp. 1161-1170 ◽  
Author(s):  
Ameen Ali Abu-Hashem ◽  
Rasha A. M. Faty

Background: 1, 3, 4-thiadiazoles, 1, 3, 4-thiadiazines and thienopyrimidines have newly attracted attention due to their forceful pharmacological activities. They showed antimicrobial, antiviral, analgesic and anti-inflammatory properties. Objective: The aim of this research is to synthesize new thiadiazolothienopyrimidines (2-10), thienopyrimidothiadiazines (11-15), quinoxaline-thienopyrimidinones (16) and thienopyrimido- thiadiazinoquinoxalinones (17) via effectual high yield procedure for assessing their antimicrobial activity. Method: A series of new 1, 3, 4-thiadiazolothienopyrimidines, thienopyrimidothiadiazines and thienopyrimidothiadiazinoquinoxalinones was prepared from 6-acetyl-3-amino-5-methyl-2-thioxo-2, 3-dihydrothieno [2, 3-d] pyrimidin-4(1H)-one (1) as the beginning material. Results: The 1, 3, 4-thiadiazoles, 1, 3, 4-thiadiazines derivatives (1-17) were synthesized in adequate to good yields (60-85%) in a stepwise effectual procedure under condition. The chemical structures of these new compounds were confirmed via many spectroscopic techniques as UV, IR, NMR, mass spectra and elemental analysis. In vitro, antimicrobial was evaluated for the synthesized compounds using minimal inhibitory concentration of these compounds against bacteria and fungi. Conclusion: The 1, 3, 4-thiadiazole and 1, 3, 4-thiadiazine derivatives (15-17) exhibited higher antimicrobial activity (Gram-positive, Gram-negative bacteria and fungi) compared with the standard antibiotic drugs; Levofloxacin (Tavanic) and Nystatin.


2021 ◽  
Vol 14 (7) ◽  
pp. 603
Author(s):  
Vanesa Pérez-Laguna ◽  
Isabel García-Luque ◽  
Sofía Ballesta ◽  
Antonio Rezusta ◽  
Yolanda Gilaberte

The present review covers combination approaches of antimicrobial photodynamic therapy (aPDT) plus antibiotics or antifungals to attack bacteria and fungi in vitro (both planktonic and biofilm forms) focused on those microorganisms that cause infections in skin and soft tissues. The combination can prevent failure in the fight against these microorganisms: antimicrobial drugs can increase the susceptibility of microorganisms to aPDT and prevent the possibility of regrowth of those that were not inactivated during the irradiation; meanwhile, aPDT is effective regardless of the resistance pattern of the strain and their use does not contribute to the selection of antimicrobial resistance. Additive or synergistic antimicrobial effects in vitro are evaluated and the best combinations are presented. The use of combined treatment of aPDT with antimicrobials could help overcome the difficulty of fighting high level of resistance microorganisms and, as it is a multi-target approach, it could make the selection of resistant microorganisms more difficult.


2017 ◽  
Vol 67 (3) ◽  
pp. 309-324 ◽  
Author(s):  
Nadjet Rezki ◽  
Mohamed Reda Aouad

AbstractThe present study describes an efficient and ecofriendly, ultrasound, one-pot click cycloaddition approach for the construction of a novel series of 1,4-disubstituted-1,2,3-triazoles tethered with fluorinated 1,2,4-triazole-benzothiazole molecular conjugates. It involved three-component condensation of the appropriate bromoacetamide benzothiazole, sodium azide and 4-alkyl/aryl-5-(2-fluorophenyl)-3-(prop-2-ynylthio)-1,2,4-triazoles4a-ethrough a Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction. This approach involvesin situgeneration of azidoacetamide benzothiazole, followed by condensation with terminal alkynes in the presence of CuSO4/Na-ascorbate in aqueous DMSO under both conventional and ultrasound conditions. Some of the designed 1,2,3-triazole conjugates6a-owere recognized for their antimicrobial activity against some bacterial and fungal pathogenic strains.


2021 ◽  
Author(s):  
Smita J. Pawar ◽  
Amol Kale ◽  
Priya Zori ◽  
Rahul Dorugade

Abstract Abstract The new series of 2-(substituted amino)-N-(6- substituted-1,3-benzothiazol-2yl) acetamide BTC(a-t) has been synthesized by appropriate synthetic route from substituted 2-amino benzothiazole. The synthesized compounds were screened experimentally for its antimicrobial property against gram positive, gram negative bacteria and fungi. Zone of inhibition and minimum inhibitory concentration of compounds was determined against selected bacterial and fungal strains. Compound BTC-j N-(6-methoxy-1,3-benzothiazol-2-yl)-2-(pyridine-3-yl amino) acetamide and compound BTC-r N-(6-nitro-1,3-benzothiazol-2-yl)-2-(pyridine-3-yl amino) acetamide found to have good antimicrobial potential. The compound BTC-j has shown good antibacterial activity against S. aureus at MIC of 12.5 µg/ml, B. subtilis at MIC of 6.25µg/ml, E. coli at MIC of 3.125µg/ml and P. aeruginosa at MIC of 6.25µg/ml. No statistical difference in antimicrobial activity of standard and test compounds was found indicating test compounds have comparable activity. Further docking study was carried out to check the probable interactions with the selected protein using V-life MDS 3.5 software. (DNA gyrase, PDB: 3G75). The dock score of compounds and antimicrobial activity found to be consistent.


Author(s):  
Mujeeb Rahman ◽  
Ping Wang ◽  
Na Wang ◽  
Yaodong Chen

The number of multidrug-resistant bacterial strains is currently increasing; thus, the determination of drug targets for the development of novel antimicrobial drugs is urgently needed. FtsZ, the prokaryotic homolog of the eukaryotic tubulin, is a GTP-dependent prokaryotic cytoskeletal protein that is conserved among most bacterial strains. In vitro studies revealed that FtsZ self-assembles into dynamic protofilaments or bundles, and it forms a dynamic Z-ring at the center of the cell, leading to septation and consequent cell division. The potential role of FtsZ in the blockage of cell division makes FtsZ a highly attractive target for developing novel antibiotics. Researchers have been working on synthetic molecules and natural products as inhibitors of FtsZ. Accumulating data suggest that FtsZ may provide the platform for the development of novel antibiotics. In this review, we summarize recent advances on the properties of FtsZ protein and bacterial cell division, as well as on the development of FtsZ inhibitors.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Sonja Ž. Đurić ◽  
Sandra Vojnovic ◽  
Tina P. Andrejević ◽  
Nevena Lj Stevanović ◽  
Nada D. Savić ◽  
...  

1,2-Bis(4-pyridyl)ethane (bpa) and 1,2-bis(4-pyridyl)ethene (bpe) were used for the synthesis of polynuclear silver(I) complexes, {[Ag(bpa)]NO3}n (1), {[Ag(bpa)2]CF3SO3.H2O}n (2) and {[Ag(bpe)]CF3SO3}n (3). In complexes 1–3, the corresponding nitrogen-containing heterocycle acts as a bridging ligand between two Ag(I) ions. In vitro antimicrobial activity of these complexes, along with the ligands used for their synthesis, was evaluated against the broad panel of Gram-positive and Gram-negative bacteria and fungi. The silver(I) complexes 1–3 showed selectivity towards Candida spp. and Gram-negative Escherichia coli in comparison to the other investigated bacterial strains, effectively inhibiting the growth of four different Candida species with minimal inhibitory concentrations (MICs) between 2.5 and 25 μg/mL and the growth of E. coli, with MIC value being 12.5 μg/mL. Importantly, complex 2 significantly reduced C. albicans filamentation, an essential process for its pathogenesis. Antiproliferative effect on the normal human lung fibroblast cell line MRC-5 was also evaluated with the aim of determining the therapeutic potential of the complexes 1–3. The interactions of these complexes with calf thymus DNA (ctDNA) and bovine serum albumin (BSA) were studied to evaluate their binding activities towards these biomolecules for possible insights on their mode of action.


Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1339 ◽  
Author(s):  
Islam H. El Azab ◽  
Nadia A.A. Elkanzi

A series of 34 new pyrimido[2,1-c][1,2,4]triazine-3,4-diones were synthesized and fully characterized using IR, NMR, MS, and microanalytical analysis. In vitro investigation of 12 compounds of this series revealed promising antimicrobial activity of the conjugates 15a and 15f–j that were tagged with electron-withdrawing groups, with sensitivities ranging from 77% to as high as 100% of the positive control. The investigation of antimicrobial activity included Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6535, Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 8739 (EC), and fungal strains Candida albicans ATCC 10231 and Aspergillus brasiliensis ATCC 16404.


1970 ◽  
Vol 6 (2) ◽  
pp. 69-75 ◽  
Author(s):  
G Nagalakshmi

1,3,4-oxadiazoles are important because of its versatile biological actions. In the present study, several 2,5-disubstituted-1,3,4-oxadiazoles (3a-o) have been synthesized by the condensation of 4-hydroxybenzohydrazide (1) with various aromatic acids (2a-o) in presence of phosphorus oxychloride. The structures of the newly synthesized compounds have been established on the basis of elemental analysis, UV, IR and 1H NMR spectral data. The synthesized compounds were screened for their in vitro growth inhibiting activity against different strains of bacteria and fungi viz., Staphylococcus aureus, Bacillus subtilis, Bacillus megaterium, Escherichia coli, Pseudomonas aeruginosa, Shigella dysenteriae, Candida albicans, Aspergillus niger and Aspergillus flavus and the results were compared with the standard antibiotics such as chloramphenicol (50?g/ml) and Griseofulvin (50?g/ml) using agar diffusion technique. Compounds 3b, 3e, 3g, 3h, 3j, 3m and 3n exhibited strong antibacterial activity and compounds 3a, 3d, 3g, 3h and 3i showed good antifungal activity. Key words: 2,5-disubstituted-1,3,4-oxadiazoles, 4-hydroxybenzohydrazide, phosphorus oxychloride, antimicrobial evaluation, agar well diffusion method. Dhaka Univ. J. Pharm. Sci. 6(2): 69-75, 2007 (December)


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