Synthesis and characterization of antibacterial 2-(pyridin-3-yl)-1H-benzo[d]imidazoles and 2-(pyridin- 3-yl)-3H-imidazo[4,5-b]pyridine derivatives (original) (raw)
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European Journal of Medicinal Chemistry, 2011
New antimicrobial agents, imidazo[1,2-a]pyridine and imidazo[2,1-b][1,3]benzothiazole, have been synthesized. Their antimicrobial activities were conducted against various Gram-positive, Gram-negative bacteria and fungi. Compounds 6c, 7a, 10b, 11a, 12b, 14a, 14b, 15a and 15b, exerted strong inhibition of the investigated bacterial and fungal strains compared to control antibiotics amoxicillin and cefixime and the antifungal agent fluconazole. Results from this study showed that the nature of the substituents on the armed aryl groups determines the extent of the activity of the fused imidazopyridine and/or imidazobenzothiazole derivatives. Preliminary structureeactivity observations revealed that bromofluoro substituents enhanced the antimicrobial activity significantly compared to other substituents.
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A novel series of 2-(5-substituted)-1,3,4-oxadiazole-2-yl)-H-imidazo[1,2,α]pyridine derivatives 5a-i and 6a-d are synthesized and characterized by IR, H NMR, C NMR and Mass spectral analysis. All the synthesized compounds were tested for there antibacterial and antifungal activity of which compound 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 6a, 6c and 6d exhibited good antimicrobial activity.
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In this study, new pyrazole, imidazole, pyrimidine derivatives having imidazo[4,5-b]indol moiety were successfully synthesized, elucidated by spectroscopic techniques, and evaluated as potential antimicrobial agents. The structure-activity relationship was investigated to obtain a better understanding of the relationship between the chemical structure of the synthesized compounds and their corresponding biological activity. Compounds 2b and 3b exhibited potent antibacterial activities against Bacillus subtilis bacteria comparable to that of Ampicillin standard. Structure-activity relationship studies revealed that the presence of withdrawing carbonyl group on 5-position of pyrazole moiety 2b, phenylpyrazole moiety 3b led to an enhancement in the antibacterial activity of pyrazole derivatives. Furthermore, the presence of carbonyl group on 2-position of the pyrimidine ring of compounds 4a, 5a and 6a has a significant effect on their antibacterial activity against Bacillus subtilis. The antifungal studies indicated that compounds 3b, 4b, 7 and 9 have comparable antifungal activity to that of standard Amphotericin B against Candida albicans and Aspergillus flavus fungi.
Bioorganic & Medicinal Chemistry, 2004
A series of triazolylcoumarins was synthesized by the cycloaddition of acetylenic derivatives to azide in the presence of Cu(I) catalyst at room temperature. All the synthesized compounds were evaluated for their anti-microbial activity against Gram-positive (B. subtilis and S. aureus), Gram-negative bacteria (K. pneumonia and P. vulgaris) and human pathogenic fungi (C. tropicalis and C. krusei), with tetracycline and fluconazole as standards for anti-microbial and anti-fungal activity. Triazolylcoumarins exhibit anti-microbial activity against all the tested pathogens, which is further supported by molecular docking studies.
Synthesis of novel imidazo[1,2-$a$]pyridines and evaluation of their antifungal activities
TURKISH JOURNAL OF CHEMISTRY, 2014
New 2-(imidazo[1,2-a ]pyridin-2-ylcarbonyl)-N-substituted hydrazinecarbothioamides (4a-j), N '-(3-substituted-4-oxo-1,3-thiazolidin-2-ylidene)imidazo[1,2-a ]pyridine-2-carbohydrazides (5a-f), and N-(nonsubstituted/4-substituted phenyl)-5-(imidazo[1,2-a ]pyridine-2-yl)-1,3,4-oxadiazole-2-amines (6a-d) were synthesized from imidazo[1,2-a ]pyridine-2-carbohydrazide (3) and evaluated for antifungal activity against Microsporum gypseum NCPF 580, M. canis, Trichophyton tonsurans NCPF 245, T. rubrum, Candida albicans ATCC 10231, and C. parapsilosis ATCC 22019 using amphotericin B as the standard. The chemical structures of the compounds were confirmed by elemental analysis, IR, 1 H NMR, 13 C NMR, HMBC (13 C, 1 H), and mass spectra. Most of the tested compounds showed moderate antifungal activity. Hydrazinecarbothioamide derivatives 4h and 4f exhibited the highest activity against M. canis (MIC: 2 µ g mL −1 and 4 µ g mL −1 , respectively).
STUDIES ON SOME NEW PYRAZOLO[3,4-c]PYRIDINE DERIVATIVES AS ANTIMICROBIAL AGENTS
2010
The increasing clinical importance of drug-resistant bacterial and fungal pathogens has lent additional urgency to microbiological research and novel antimicrobial compounds development. For this aim, a series of N-[(Benzhydryl) / (l-phenylethyl)]-2-pyrazolo[3,4-c]pyridin-l-yl acetamide derivatives (3a-m) were synthesized by reacting 2-chloro-N-(benzhydryl)acetamide (la) / 2-chloro-N(1-phenylethyl)acetamide (lb) and pyrazolo[3,4-c]pyridine derivatives (2). The chemical structures of the compounds were elucidated by elemental analyses, IR, H-NMR, FAB-MS spectral data. Their antimicrobial activities against E. coli (ATCC 11229), S. aureus (ATCC 6538), B. cereus (ATCC 11778), P. mirabilis (ATCC 14153), P. aeruginosa (ATCC 1539), K. pneumoniae (ATCC 4352), C albicans (ATCC 26555), C guilliermondii (KUEN 998), C pseudotropicalis (kefyr) (KUEN 1014), and C krusei (ATCC 6258) were investigated. The results showed that some of the compounds have slight activity against B. cereus and S. aure...
Journal of Medicinal Chemistry, 2002
The synthesis, anti-Candida activity, and quantitative structure-activity relationship (QSAR) studies of a series of 2,4-dichlorobenzylimidazole derivatives having a phenylpyrrole moiety (related to the antibiotic pyrrolnitrin) in the R-position are reported. A number of substituents on the phenyl ring, ranging from hydrophobic (tert-butyl, phenyl, or 1-pyrrolyl moiety) to basic (NH 2 ), polar (CF 3 , CN, SCH 3 , NO 2 ), or hydrogen bond donors and acceptor (OH) groups, were chosen to better understand the interaction of these compounds with cytochrome P450 14-Rlanosterol demethylase (P450 14DM ). Finally, the triazole counterpart of one of the imidazole compounds was synthesized and tested to investigate influence of the heterocyclic ring on biological activity. The in vitro antifungal activities of the newly synthesized azoles 10p-v,x-c′ were tested against Candida albicans and Candida spp. at pH 7.2 and pH 5.6. A CoMFA model, previously derived for a series of antifungal agents belonging to chemically diverse families related to bifonazole, was applied to the new products. Because the results produced by this approach were not encouraging, Catalyst software was chosen to perform a new 3D-QSAR study. Catalyst was preferred this time because of the possibility of considering each compound as a collection of energetically reasonable conformations and of considering alternative stereoisomers. The pharmacophore model developed by Catalyst, named HYPO1, showed good performances in predicting the biological activity data, although it did not exhibit an unequivocal preference for one enantiomeric series of inhibitors relative to the other. One aromatic nitrogen with a lone pair in the ring plane (mapped by all of the considered compounds) and three aromatic ring features were recognized to have pharmacophoric relevance, whereas neither hydrogen bond acceptor nor hydrophobic features were found. These findings confirmed that the key interaction of azole antifungals with the demethylase enzyme is the coordination bond to the iron ion of the porphyrin system, while interactions with amino acids localized in proximity of heme could modulate the biological activity of diverse antifungal agents. In conclusion, HYPO1 conveys important information in an intuitive manner and can provide predictive capability for evaluating new compounds.
As attempt to cope the microbial drug-resistance, new derivatives of 2-pyridinone and 2-iminochromene with biologically active pyrrole core were designed and synthesized. The 2-pyridone derivatives were synthesized via ring closure of 2-cyano-N'-((1-methyl-1H-pyrrol-2-yl)methylene)acetohydrazide by 1,3-dicarbonyl compound (acetylacetone) or arylidene malononitriles. The 2-iminochromene derivatives were obtained via the cyclocondensation reaction of cyanoacetamide by o-hydroxy aldehyde derivatives to furnish chromene derivatives. The antibacterial and antifungal activities for the synthesized compounds were investigated. All of the 2-pyridinone and 2-iminochromene derivatives showed moderate activity toward both of G -ve and G + ve bacteria (S. aureus).