Nurten Altanlar

Synthesis of some new 2-substituted-phenyl-1H-benzimidazole-5-carbonitriles and their potent activity against Candida species.

New 2-substituted-phenyl-1H-benzimidazole-5-carboxylic acids (35, 38), ethyl-5-carboxylate (36), -5-carboxamides (37, 39),-5-carboxaldehyde (42), -5-chloro (40), -5-trifluoromethyl (41), and -5-carbonitriles (44-53, 55-67), -6-carbonitrile (54) were prepared and evaluated in vitro against Candida species. The cyano substituted compounds 53, 57, 58 and 61 exhibited the greatest activity with MIC values of 3.12 microg/mL, values similar to that of fluconazole.

Synthesis and antimicrobial activity of some novel 2,5- and/or 6-substituted benzoxazole and benzimidazole derivatives.

A new series of 2,5- and/or 6-substituted benzoxazoles (7a-f), benzimidazoles (8a-g) holding cyclohexyl or cyclopentyl moieties at position 2 and 5- or 6-substituted-2-cyclohexylaminomethylbenzoxazoles (9a, b) was synthesized in order to determine their antimicrobial activities and feasible structure-activity relationships. The synthesized compounds were tested in vitro against three Gram-positive, two Gram-negative bacteria and the yeast Candida albicans in comparison with several control drugs. Microbiological results showed that the synthesized compounds were possessing a broad spectrum of antibacterial activity against the tested microorganisms. 5-Chloro-2-(2-cyclohexylethyl)benzimidazole (8g) was found as the most active compound against the screened Gram-positive bacteria strains at a minimum inhibitory concentration (MIC) value of 12.5 microg/ml. However, it exhibited lower antibacterial potency than the compared control drugs. On the other side, compounds 7-9 indicated significant antibacterial activity against the Gram-negative enterobacter Pseudomonas aeruginosa having MIC values of 50 microg/ml, providing either the same effect as tetracycline or higher activity than streptomycin, but showing less potency than the compared control drug gentamycin. Moreover, the synthesized compounds also possessed antimycotic activity against the yeast C. albicans showing MIC values between 25-50 microg/ml.

Synthesis and antimicrobial activities of some new benzimidazole derivatives.

Some benzimidazolylbenzamides were synthesized and their antimicrobial activities against Staphylococcus aureus, Streptococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans evaluated. It was shown that the compound 14 exhibited the best activity against B. subtilis, P. aeruginosa and C. albicans.

Synthesis and in vitro antimicrobial activity of some novel substituted benzimidazole derivatives having potent activity against MRSA.

The novel benzimidazole derivatives (3, 5, 8, 9, 12-14, 18-41) were prepared in this paper and the antimicrobial activities of these compounds against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA, standard and clinical isolates), Bacillus subtilis, Escherichia coli and Candida albicans were evaluated. Compounds 24-26 which have no substitution of N-1 position displayed better antibacterial activities than those of standards (ciprofloxacin, ampicillin and sultamicillin) against both the drug-resistant bacteria (MRSA, standard and clinical isolates). These derivatives (24-26), 2,5,6-trihalogenobenzimidazole analogues (8, 12), 5,6-dichloro-2-amino derivative (13), and 5-chloro-2-(4-benzyloxyphenyl)benzimidazole (35) exhibited the most potent antibacterial activity with MIC 3.12 microg/ml against S. aureus.

Synthesis and microbiological activity of some novel 5-benzamido- and 5-phenylacetamido- substituted 2-phenylbenzoxazole derivatives

The synthesis and microbiological activity of a new series of 5-benzamido- and 5-phenylacetamidosubstituted-2-phenylbenzoxazole derivatives (1-26) were described. The in vitro microbiological activity of the compounds was determined against Gram-positive, Gram-negative bacteria and the yeast Candida albicans in comparison with standard drugs. Microbiological results indicated that the synthesized compounds possessed a broad spectrum of activity against the tested microorganisms. The compounds 1, 21, 25 showed higher activity than tetracycline and streptomycin against Pseudomonas aeruginosa.

Investigation of Antimicrobial Activities of Indole-3-Aldehyde Hydrazide/Hydrazone Derivatives

Background: Indoles and hydrazone-type compounds constitute an important class of compounds for new drug development in order to discover an effective compound against multi-drug-resistant microbial infections. Methods: A series of indole-3-aldehyde and 5-bromoindole-3-aldehyde hydrazide and hydrazones was evaluated for their in vitro antimicrobial activities using the 2-fold serial dilution technique against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Escherichia coli, Bacillus subtilis and Candida albicans. The minimum inhibitory concentration (MIC) was determined for test compounds and for the reference standards sultamicillin, ampicillin, fluconazole and ciprofloxacin. Results: Compounds possessed a broad spectrum of activity having MIC values of 6.25–100 mg/ml against the tested microorganisms. Compounds 1a–1j, in particular, displayed better activity against MSRA and significant activity against S. aureus relative to ampicillin. Unexpectedly, indole nicotinic acid hydrazides showed no significant activity while indole anisic acid hydrazides displayed better activity. Conclusion: The results may be instructive to researchers attempting to gain more understanding of the antimicrobial activity of indole hydrazide/hydrazone-type compounds.

Synthesis and microbiological activity of some N-(o-hydroxyphenyl)benzamides and phenylacetamides as the possible metabolites of antimicrobial active benzoxazoles: part II

The synthesis of some N-(o-hydroxyphenyl)benzamides and benzacetamides (2a-2p) in order to determine their in vitro antimicrobial activity against two Gram-positive bacteria, three Gram-negative bacteria and the fungus Candida albicans is described. The new compounds were compared with several control drugs. The derivative 2g, 4-amino-N-(o-hydroxyphenyl)benzamide, was found active at an MIC value of 25 microg/ml against the Gram-negative microorganism Klebsiella pneumoniae. Most of the compounds exhibited antibacterial activity at an MIC value of 25 microg/ml against Pseudomonas aureginosa. For the antifungal activity against C. albicans, compounds 2e, 2h and 2m were found more active than the other derivatives (MIC 12.5 microg/ml). The antimicrobial activity of some of these benzamide and phenylacetamide derivatives (2a, 2b, 2f, 2g, 2h and 2k), possible metabolites of benzoxazoles, was also compared with that of the cyclic analogues 3-8. Compound 2f possesses two dilutions better antifungal activity than its cyclic analogue the benzoxazole derivative 5 against C. albicans, while having one dilution better antibacterial activity against Streptococcus faecalis and K. pneumoniae.

Synthesis, antifungal and antioxidant screening of some novel benzimidazole derivatives

Some novel benzimidazole derivatives were synthesized and their in vitro effects on rat liver microsomal NADPH-dependent lipid peroxidation (LP) level, ethoxyresorufin O-deethylase (EROD) and antifungal activities were determined. A significant decrease in male rat liver microsomal LP level was noted by compounds 4c (52%), 4e (58%) and 4h (43%) at 10− 3 M concentration. Compounds 4c (100.0%), 4h (100.0%), 5c (98.0%) and 5h (100.0%) inhibited the microsomal ethoxyresorufin O-deethylase (EROD) enzyme activity better than that of the specific inhibitor caffeine (85%). Among these compounds, only compounds 4b and 4h exhibited moderate activity against C.albicans whereas the others had weak effects.

Synthesis and Antimicrobial Activity of Some New 2-Phenyl-N-substituted Carboxamido-1H-benzimidazole Derivatives

Some 1H‐benzimidazole‐carboxamide derivatives were prepared and their antimicrobial activities against Staphyloccus aureus, Escherichia coli and Candida albicans evaluated. Compounds 18, 22, and 25 exhibited the best activity against Candida albicans.

Synthesis and antimicrobial activity of some novel 2-(p-substituted-phenyl)-5-substituted-carbonylaminobenzoxazoles

A series of 2-(p-substituted-phenyl)-5-substituted-carbonylamino benzoxazole derivatives (5-22) was synthesized and their antimicrobial activities determined in comparison to several control drugs. The synthesized compounds were tested in vitro against Staphylococcus aureus, Streptococcus faecalis and Bacillus subtilis as Gram-positive, Pseudomonas aeruginosa and Escherichia coli as Gram-negative bacteria and the yeast Candida albicans. Microbiological results showed that the compounds possessed a diffuse spectrum of antibacterial activity against these microorganisms. Compound 9 which bears a phenylacetamido moiety at position 5 and a 4-fluorophenyl group at the 2-position of benzoxazole ring was the most active derivative against S. aureus, S. faecalis and P. aeruginosa with a MIC value of 12.5 microg/ml. Compound 11 provided higher potency than the other tested compounds against B. subtilis at a MIC value of 12.5 microg/ml. Compounds 5-22 showed antifungal activity against C. albicans with MIC values between 50 and 12.5 microg/ml.