scholarly journals Microwave Assisted Synthesis and Antimicrobial Evaluation of Schiff Bases of Indole-3-aldehyde

2011 ◽  
Vol 8 (1) ◽  
pp. 305-311 ◽  
Author(s):  
Priyanka Kamaria ◽  
N. Kawathekar ◽  
Prerna Chaturvedi

In order to develop new antimicrobial agents, a series of Schiff bases of indole-3-aldehyde were synthesized by microwave assisted synthesis by takingDMFas solvent and evaluated for their antimicrobial activity. All the synthesized compounds were characterized byIR,1HNMRand mass spectral analysis. All compounds were tested against five gram positive and five gram negative bacterial strains and one fungal strain. All compounds exhibited better activity against gram positive strains than against gram negative strains and the compounds were found more active againstS.aureusandB.subtilis.

Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.


Author(s):  
Mohammad Hassan Moshafi ◽  
Ali Peymani ◽  
Alireza Foroumadi ◽  
Mohammad Reza Zabihi ◽  
Farzad Doostishoar

Introduction: Nitrofurans and nitroimidazoles are broad-spectrum antimicrobial agents, which affect the microbial DNA. The aim of the present study was to evaluate the new derivatives of these two groups of antimicrobials against certain Gram-positive and Gram-negative bacterial strains. Materials and Methods: Seven new derivatives of nitrofurans and nitroimidazoles were synthesized, and 6.4 mg of each derivative was dissolved in dimethyl sulfoxide. Then, 8 serial dilutions (0.5, 1, 2, 4, 8, 16, 32, and 64 μg/ml) of each derivative was prepared using Muller-Hinton broth, and the minimum inhibitory concentration for each derivative was measured and compared to ciprofloxacin (standard). Results: All the derivatives had no antibacterial effects against Gram-negative bacteria (minimum inhibitory concentration > 64 μg/ml); only 2-(5-nitro-2-furyl)-5-(n-pentylsulfunyl)-1,3,4-thiadiazole exhibited mild antibacterial effects against Klebsiella pneumonia (minimum inhibitory concentration of 16-32 μg/ml). The antibacterial effects of the derivatives against Gram-positive bacteria also showed variations from complete inhibition of the growth of Staphylococcus epidermidis and Bacillus subtilis (minimum inhibitory concentration < 0.5 μg/ml) by 2-(5-nitro-2-furyl)-5-(n-buthylthio)-1,3,4-thiadiazole to no inhibition of S. epidermidis and streptococcus pyogenes. Conclusion: These compounds have weak antibacterial effects; only two derivatives showed antibacterial effects similar to that of the positive control.


2021 ◽  
Vol 33 (7) ◽  
pp. 1525-1529
Author(s):  
Parmesh Kumar Dwivedi ◽  
Devdutt Chaturvedi

A new series of fluorinated sulfur inserted benzimidazole analogues Za-i were synthesized and characterized. The new compounds were screened for their antimicrobial and antioxidant potential. The synthesized compounds were obtained by multiple step synthesis, initiating from the synthesis of 5-(difluoromethoxy)-1H-benzimidazole-2-thiol X. The compounds Ya-i prepared by reacting differently substituted anilines with chloroacetylchloride and triethylamine in DMF. Finally, the compound X was reacted with different derivatives of 2-chloro-N-phenylacetamide resulting in formation of titled compounds Za-i. The synthesized compounds (Za-Zi) were characterized by spectral analysis viz.1H & 13C NMR, mass spectra, elemental analysis and IR. The in vitro antimicrobial potential against Gram-positive (S. aureus and E. faecalis) and Gram-negative bacterial (E. coli and P.aeruginosa) strains as well as fungi (A. niger and C. albicans) was recorded for the obtained compounds. Some of the compounds exhibited encouraging results (in MIC) against Gram-positive and Gram-negative bacterial strains. These studies thus suggest that the designed sulfur inserted fluoro-benzimidazoles scaffold may serve as new promising template for further amplification as antimicrobial agents.


2016 ◽  
Vol 29 (1) ◽  
pp. 37-40
Author(s):  
Amna Ali ◽  
M Saleem Haider ◽  
Sobia Mushtaq ◽  
Ibatsam Khokhar ◽  
Irum Mukhtar ◽  
...  

The antimicrobial agents of bacteria isolated from different rhizosphere of fruits and vegetables soil in Lahore. Of ten species, five were gram-negative (Escherichia coli, Pseudomonas fluorescence, Klebsiella pneumoniae, Salmonella typhii, Brachybacterium faecium); other five were gram positive and identified as Bacillus farraginis, Kurthia gibsonii, Aureobacterium liquefaciens, Curtobacterium albidum, Micrococcus lylae. The antagonistic potential of bacterial strains was assessed by the well diffusion technique and results indicating varying degree of biocontrol activity against pathogenic strain of X. campestris. Out of ten bacterial species, E. coli (gram negative) and C. albidum (gram positive) showed a high prevalence of resistance with reduction of 4.2cm and 4.1cm zone diameter respectively. The minimum inhibitory volume (MIV) to two bio-agents was determined for X. campestris from range 10-100 ?L. E. coli (volume required to inhibit < 20 ?L) and C. albidum (volume required to inhibit < 40 ?L) exhibited good activity against pathogen. These results provide information on the prevalence of resistant bacterial strains with the MIV of organisms and indicate the possibility of using these bacterial species as bio-agent against X. campestris.Bangladesh J Microbiol, Volume 29, Number 1, June 2012, pp 37-40


2020 ◽  
Vol 71 (2) ◽  
pp. 422-435
Author(s):  
Farag A. El-Essawy ◽  
Abdulrahman I. Alharthi ◽  
Mshari A. Alotaibi ◽  
Nancy E. Wahba ◽  
Nader M. Boshta

A novel series of 3-, 4-substituted, and 3,4-di substituted quinazoline derivatives were prepared via various cyclized regents and most of the newly prepared compounds evaluated for their antimicrobial activities in vitro against Gram-positive, Gram-negative bacterial strains and fungi strains. The structures of the quinazoline derivatives have been confirmed using spectroscopic analyses (IR, NMR, and EI-MS). Some of the synthesized derivatives displayed a moderate antimicrobial activity in comparison with reference drugs, for example compounds 13d, 15a, 17b, 18b, 18d, 25, and 29a-c. Among the synthesized compounds, the pyrimidoqunazoline derivative 6c elicited the highest activity.


Author(s):  
Shipra Baluja ◽  
Sumitra Chanda

Some Schiff bases of pyrazole and 4-amino antipyrine have been synthesized. The antibacterial screening of these synthesized compounds was done in dimethyl formamide against four Gram positive bacteria viz.Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidids and Micrococcus luteus, and three Gram negative bacteria viz. Proteus mirabilis, Escherichia coli and Klebsiella aerogenes. It is observed that in comparison to Schiff bases of 4-amino antipyrine, pyrazole Schiff bases are better for inhibition for these selected Gram positive and Gram negative bacterial strains.


2004 ◽  
Vol 69 (12) ◽  
pp. 991-998 ◽  
Author(s):  
Yogesh Vaghasiya ◽  
Rathish Nair ◽  
Mayur Soni ◽  
Shipra Baluja ◽  
Sumitra Shanda

Schiff bases derived from 4-aminoantipyrine and vanillin were evaluated for their potential as antibacterial agents against some Gram positive and Gram negative bacterial strains. The antibacterial activity was studied against P. pseudoalcaligenes ATCC 17440, P. vulgaris NCTC 8313, C. freundii ATCC 10787 E. aerogenes ATCC 13048, S. subfava NCIM 2178 and B. megaterium ATCC 9885. The determination of the antibacterial activity was done using the Agar Ditsh method. The Schiff bases produced were: (1) 4-(4-hydroxy 3-methoxybenzylideneamino) -1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one [VV1]; (2) 4-(benzylideneamino) -1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one [VY2]); (3) 4-[(furan-3-ylmethylene) amino ]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one [VY3]?; (4) 4-(4-methoxybenzylideneamino) -1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one [VY4]?; (5) 2-methoxy-4-[(4-methoxyphenylimino) methyl ]phenol [VY5]; (6) 4-[(2,4-dimethylphenylimino) methyl]-2-methoxyphenol [VY6]); (7) 2-methoxy-4-(naphthalene-1-yliminomethyl) phenol [VY7]?and (8) 4-[(4-hydroxy-3-methoxybenzylidene)amino]-N-(5-methylisoxazol 3-yl)benzenesulfonamide [VY8]. The antibacterial activity was evaluated in two polar solvents, DMSO and DMF. The Schiff bases derived from vanillin as the central molecule with 2,4-dimethylaniline and sulphamethoxazole as the side chain in DMSO effectively inhibited the investigated bacteria and appear to be promising antimicrobial agents.


2017 ◽  
Vol 82 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Priyanka Khatkar ◽  
Sonika Asija ◽  
Namita Singh

In the present work, a series of twenty-four organotin (IV) complexes of the type [R2SnLCl, R3SnL] have been synthesized by the condensation of 2-benzoylpyridine Schiff bases with R2SnCl2, R3SnCl (R= Me, n-Bu, Ph) in 1:1 molar ratio. These complexes were well characterized by IR, 1H, and 13C, 119Sn NMR, XRD and mass spectral techniques. In the search for biologically more effective antimicrobial agents, all the synthesized ligands and organotin complexes were evaluated for their in vitro antimicrobial activities against two Gram positive and two Gram negative bacteria, and two fungal strains by serial dilution method. The results of spectral data revealed that the complexes formed were hexacoordinated with tridentate ligands which coordinated through azomethine N, pyridine N and carboxylate O ligation sites. The ligands on co-ordination with tin metal showed a discernible augmentation in biocidal activity, however, the Ph and Bu complexes were found to be more intoxicating. The results revealed that the synthesized complexes were more noxious towards Gram positive strains as compared to Gram negative strains which may be attributed to the presence of an outer lipid membrane of lipopolysaccharides.


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