Premlata Kumari

Synthesis of benzimidazolyl-1,3,4-oxadiazol-2ylthio-N-phenyl (benzothiazolyl) acetamides as antibacterial, antifungal and antituberculosis agents

To affiliate multiple bioactivities in a compact heteronuclei, two series of benzimidazole based 1,3,4-oxadiazoles were synthesized and assessed in vitro for their efficacy as antimicrobial agents against eight bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, Shigella flexneri), four fungi (Aspergillus niger, Aspergillus fumigatus, Aspergillus clavatus, Candida albicans) and Mycobacterium tuberculosis H37Rv and best results were observed amongst the N-benzothiazolyl aetamide series. The lipophilicity (LogP) influence on the biological profile (MICs) of the prepared products was also discussed. Upon biological screening, it was observed that the majority of the compounds were found to possess a significant broad spectrum antimicrobial (3.12-25 μg/mL of MIC) and antitubercular (6.25-25 μg/mL of MIC) potential. The structural assignments of the new products were done on the basis of IR, (1)H NMR, (13)C NMR spectroscopy and elemental analysis.

Synthesis and studies of novel 2-(4-cyano-3-trifluoromethylphenyl amino)-4-(quinoline-4-yloxy)-6-(piperazinyl/piperidinyl)-s-triazines as potential antimicrobial, antimycobacterial and anticancer agents

A series of novel s-triazine analogs were synthesized and characterized by IR, (1)H NMR, (13)C NMR, (19)F NMR spectroscopy and elemental analysis. Preliminary screening of target compounds against eight bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, Shigella flexneria), four fungi (Aspergillus niger, Aspergillus fumigatus, Aspergillus clavatus, Candida albicans) and Mycobacterium tuberculosis H37Rv indicated that 5d, 5h, 5n, 5p, 5q, 5r, 5s, 5t and 5u were the most active compounds among twenty one studied. Thus, they were further subjected to in vitro biological evaluation against human prostate cancer cell line (DU-145) and the results indicate that two compounds 5n and 5s were markedly active.

Antimicrobial, anti-TB, anticancer and anti-HIV evaluation of new s-triazine-based heterocycles.

BACKGROUND The acquirement of resistance by microorganisms to the antimicrobial arsenal is a threat to public health. A recent WHO report estimated that 1.3 million HIV-negative people and 0.38 million HIV-positive people died from TB in 2009. Various forms of cancer account for a high percentage of deaths in both women (breast cancer) and men (prostate cancer). RESULTS & DISCUSSION In vitro activity assessment of newly constructed s-triazines against a panel of microorganisms including bacteria, fungi and Mycobacteria demonstrated that the compounds are of immense attraction for impending drug discovery. They were further examined for in vitro activity against breast cancer and prostate cancer cell lines, as well as HIV-1 (III(B)) and HIV-2 (ROD) viral strains. Proposed structural confirmation studies by IR, (1)H NMR, (13)C NMR, (19)F NMR spectroscopy and elemental analysis were in accordance. CONCLUSION Activity profiles of the products may contribute considerably to future drug-discovery studies.

Synthesis and biological evaluation of some thiazolidinones as antimicrobial agents.

A novel series of thiazolidinone derivatives namely 4-(4-dimethylamino-6-{4-[5-(4-ethylpiperazin-1-ylmethyl)-4-oxo-2-phenylthiazolidin-3-yl]-phenylamino}-[1,3,5]triazin-2-yloxy)-1-methyl-1H-quinolin-2-one have been synthesized from the key intermediate 4-[4-(4-aminophenylamino)-6-dimethylamino-[1,3,5]triazin-2-yloxy]-1-methyl-1H-quinolin-2-one (7). Condensation reaction of compound 7 with different aldehyde derivatives were performed to obtain Schiff base derivatives, which after cyclization gave thiazolidinones and finally they were reacted with N-ethylpiperazine to get target compounds. The newly synthesized compounds were evaluated for their antimicrobial activity against eight bacterial strains (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, Shigella flexneri) and four fungal strains (Aspergillus niger, Candida albicans, Aspergillus fumigatus, Aspergillus clavatus).

In vitro antimicrobial assessment of coumarin-based s -triazinyl piperazines

A series of 1,3,5-triazine derivatives that contain aniline, coumarins (4-hydroxy coumarin and 7-hydroxy-4-methyl coumarin) and different piperazine moieties as substituent on the carbon atoms of the triazine ring have been synthesized by a simple and efficient synthetic protocol. Comparative studies were performed on above series, which were synthesized with conventional and microwave heating methods. The microwave method was observed to be more beneficial as it provides an increase in yield and 90–95% reduction time. All the synthesized compounds were then examined for their efficacy against two Gram −ve bacteria (Escherichia coli and Pseudomonas aeruginosa), two Gram +ve bacteria (Staphylococcus aureus and Bacillus subtilis) and two fungal species (Candida albicans and Aspergillus niger) with an intent to overcome multiple drug resistance to the pathogenic strains. All the synthesized compounds were structurally elucidated by IR, 1H NMR, 13C NMR and elemental analysis.

A new class of 2-(4-cyanophenyl amino)-4-(6-bromo-4-quinolinyloxy)-6-piperazinyl (piperidinyl)-1,3,5-triazine analogues with antimicrobial/antimycobacterial activity.

This study presents the synthesis and in vitro pharmacological evaluations of novel 2-(4-cyanophenyl amino)-4-(6-bromo-4-quinolinyloxy)-6-piperazinyl (piperidinyl)-1,3,5-triazines. The title compounds were assayed for their in vitro antimicrobial activity against eight bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, Shigella flexneria) and four fungi (Aspergillus niger, Aspergillus fumigatus, Aspergillus clavatus, Candida albicans) using paper disc diffusion and agar streak dilution method as well as against Mycobacterium tuberculosis H37Rv strain using BACTEC MGIT and Lowenstein-Jensen MIC method. The bioassay results indicate that nine compounds namely 5d, 5h, 5n, 5p, 5q, 5r, 5s, 5t and 5u could be considered as possible potential agents with dual antimicrobial and antimycobacterial activities. The structures of the compounds were elucidated with the aid of IR, 1H NMR, 13C NMR, 19F NMR spectroscopy and CHN analysis.

In vitro antimicrobial and antimycobacterial activity of some chalcones and their derivatives

In this study, novel series of chalcone derivatives, namely, 4-[4-(3-phenyl-acryloyl)-phenylamino]-chromen-2-one (5a–k) have been synthesized from the intermediate 4-(4-acetyl-phenylamino)-chromen-2-one (4). Cyclization reaction of chalcone (5a–k) with hydrazine hydrate, guanidine nitrate, and malononitrile gives the corresponding 4-[4-(1-acetyl-5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-phenylamino]-chromen-2-one (6a–k), 4-[4-(2-amino-6-phenyl-pyrimidin-4-yl)-phenylamino]-chromen-2-one (7a–k), and 2-amino-6-[4-(2-oxo-2H-chromen-4-ylamino)-phenyl]-4-phenyl-nicotinonitrile (8a–k) derivatives were synthesized. The newly synthesized compounds were evaluated for their antimycobacterial activity and antimicrobial activity against eight bacteria (S.aureus, B. cereus, E. coli, P. aeruginosa, K. pneumoniae, S. typhi, P. vulgaris, and S. flexneri) and four fungi (A. niger, C. albicans, A. fumigatus, and A. clavatus).

Synthesis of novel 3-(5-sulfanyl-1,3,4-oxadiazol-2-yl)-2H-chromen-2-one condensed s-triazinyl piperazines and piperidines as antimicrobial agents

Synthesis and antimicrobial activity of a new series of 3-(5-sulfanyl-1,3,4-oxadiazol-2-yl)-2H-chromen-2-ones based on various substituted piperazines and piperidines incorporating a 1,3,5-triazine moiety are reported in this article. 3-{5-[(4,6-dichloro-1,3,5-triazin-2-yl)sulfanyl]-1,3,4-oxadiazol-2-yl}-2H-chromen-2-one 3 was obtained by the reaction of 2,4,6-trichloro-1,3,5-triazine 1 with 3-(5-sulfanyl-1,3,4-oxadiazol-2-yl)-2H-chromen-2-one 2 which was obtained by following the method reported in the literature. Intermediate 3 was then condensed with 8-hydroxyquinoline 4 to form 3-(5-{[4-chloro-6-(quinolin-4-yloxy)-1,3,5-triazin-2-yl]sulfanyl}-1,3,4-oxadiazol-2-yl)-2H-chromen-2-one 5. This was further treated with various substituted piperazines and piperidines to obtain the title compounds 7a–u, which were then subjected to determine their in vitro biological efficacy against bacterial and fungal strains as two Gram-positive bacteria (S. aureus, B. cereus), six Gram-negative bacteria (E. coli, P. aeruginosa, K. pneumoniae, S. typhi, P. vulgaris, and S. flexneria) and two fungal species (A. niger, and C. albicans) with an intent to develop novel class of antimicrobial agents. The results indicate that some of the novel s-triazines have noteworthy activity in MIC (μg/ml) and zone of inhibition (mm) indicating potential leads for further drug discovery study. All the final compounds were structurally elucidated on the basis of IR, 1H NMR, 13C NMR, 19F NMR spectroscopy, and elemental analysis.

New Quinolinyl–1,3,4–Oxadiazoles: Synthesis, In Vitro Antibacterial, Antifungal and Antituberculosis Studies

In order to generate hybrid antimicrobial remedies with novel mode of action, two series of quinoline based 1,3,4-oxadiazole derivatives condensed with N-aryl/benzothiazolyl acetamides were synthesized and the MIC values of the compounds towards eight reference bacterial strains (S. aureus, B. cereus, E. coli, P. aeruginosa, K. pneumoniae, S. typhi, P. vulgaris, S. flexneri), four fungi (A. niger, A. fumigatus, A. clavatus, C. albicans) and Mycobacterium tuberculosis H37Rv were assayed in vitro. Quinoline-6-carboxlic acid was treated with thionyl chloride in refluxing methanol to obtain the corresponding ester derivative to be hydrazinolyzed by 99% hydrazine hydrate in ethanol to produce carbohydrazide intermediate. The carbohydrazide precursor underwent cyclization by carbon disulfide and ethanolic KOH to construct 5-quinolinyl-6-yl-1,3,4-oxadiazol-2-thiol. Substituted 2-chloro-N-phenyl(benzothiazolyl)aceta-mide derivatives were then condensed to 1,3,4-oxadiazole nucleus via sulphur linkage to yield the desired products. Target products bearing N-benzothiazolyl-2-chloroacetamides displayed good inhibitory potential. The biological screening identified that many final analogues exhibited a significant inhibition of the growth of microorganisms at 3.12-25 μg/mL of MIC, which were comparable to control drugs. The influence of the presence of various functional groups to the phenyl/benzothiazolyl ring on activity profiles was investigated. The proposed structures of the newly prepared products were confirmed with the aid of IR, 1H NMR, 13C NMR spectroscopy and elemental analysis. These results may provide new insights in the design of a novel pool of bioactive templates.

Synthesis of 3-{4-[4-dimethylamino-6-(4-methyl-2-oxo-2H-chromen-7-yloxy)-[1,3,5]triazin-2-ylamino]-phenyl}-2-phenyl-5-(4-pyridin-2-yl-piperazin-1-ylmethyl)-thiazolidin-4-one and their biological evaluation

A novel series of thiazolidinone derivatives namely 3-{4-[4-dimethylamino-6-(4-methyl-2-oxo-2H-chromen-7-yloxy)-[1,3,5]triazin-2-ylamino]-phenyl}-2-phenyl-5-(4-pyridin-2-yl-piperazin-1-ylmethyl)-thiazolidin-4-one have been synthesized from the intermediate 7-[4-(4-amino-phenylamino)-6-dimethylamino-[1,3,5]triazin-2-yloxy]-4-methyl-chromen-2-one (7). Condensation reaction of compound 7 with different aldehyde derivatives were performed to give Schiff base derivatives, which after cyclization gave thiazolidinones and they were incorporated with 1-pyridin-2-yl-piperazine to get target compounds. The newly synthesized compounds were evaluated for their antimicrobial activity against eight bacteria (S.aureus, B. cereus, E. coli, P. aeruginosa, K. pneumoniae, S. typhi, P. vulgaris, and S. flexneria) and four fungi (A. niger, C. albicans, A. fumigatus, and A. clavatus).