N. Suchetha Kumari

Synthesis of some new 2,4-disubstituted thiazoles as possible antibacterial and anti-inflammatory agents

A series of arylthioureas (1), aromatic aldehyde thiosemicarbazones (2) and 5-aryl-2-furfuraldehyde thiosemicarbazones (3) were condensed with 2,4-dichloro-5-fluorophenacyl bromide to yield respective arylaminothiazoles, arylidene/5-aryl-2-furfurylidene hydrazinothiazoles (4). The newly synthesized compounds were characterized by IR, 1H-NMR and mass spectral studies. These compounds were also screened for their antibacterial and anti-inflammatory activities. Two of the newly synthesized compounds showed anti-inflammatory activity comparable with that of Ibuprofen.

Synthesis and antimicrobial activities of novel 1,5-diaryl pyrazoles.

Novel 1,5-diaryl pyrazole derivatives viz. 5-(4-chlorophenyl)-1-(4-fluorophenyl)-1H-pyrazole-3-carboxamides (2a-e, 3, 3a-f), 2-(5-(4-chlorophenyl)-1-(4-fluorophenyl)-1H-pyrazole-3-yl)thiazoles (6a-c,7, 8, 9a-c, 10, 11) were synthesized by varying the active part (amide group) of pyrazole, characterized using IR, (1)H NMR, mass spectral data and screened for their antibacterial activity against Escherichia coli (ATTC-25922), Staphylococcus aureus (ATTC-25923), Pseudomonas aeruginosa (ATTC-27853), Klebsiella pneumonia. Similarly all these compounds were screened for their antifungal activity against Aspergillus flavus (NCIM No. 524), Aspergillus fumigates (NCIM No. 902), Penicillium marneffei and Trichophyton mentagrophytes. Interestingly all the synthesized compounds exhibited good antibacterial (except 2a-c, 8, 9a) and antifungal activity (except 2a-c, 6a, 8, 9a).

Synthesis and biological evaluation of some 1,3,4-oxadiazole derivatives.

The acid hydrazides (2) derived from ibuprofen and 4-methylthiophenyl acetic acids have been subjected to cyclization with carbon disulphide under basic conditions to yield 1,3,4-oxadiazol-2-thiones (3) which on aminomethylation with formaldehyde and secondary amines afforded a series of Mannich bases (4 and 5). Purity of the compounds has been confirmed by TLC. Structures of these compounds were established on the basis of elemental analyses and spectral studies. The newly synthesized compounds were evaluated for their anti-inflammatory, analgesic, ulcerogenic and antimicrobial activities.

Synthesis of some novel bioactive 4-oxy/thio substituted-1H-pyrazol-5(4H)-ones via efficient cross-Claisen condensation

alpha-Oxy/thio substituted-beta-keto esters were synthesized through an efficient cross-Claisen condensation of aryl oxy/thio acetic acid ethyl esters with acid chlorides, then it is converted in situ into 4-oxy/thio substituted-1H-pyrazol-5(4H)-ones by the addition of hydrazine or hydrazine derivatives and screened for their antibacterial, antifungal activities.

Design, synthesis of some new (2-aminothiazol-4-yl)methylester derivatives as possible antimicrobial and antitubercular agents.

A series of (2-aminothiazol-4-yl)methylester (5a-t) derivatives were synthesized in good yields and characterized by (1)H NMR, (13)C NMR, mass spectral and elemental analyses. The crystal structure of 5a was evidenced by X-ray diffraction study. The compounds were evaluated for their preliminary in vitro antibacterial, antifungal activity and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The synthesized compounds displayed interesting antimicrobial activity.

Design and synthesis of positional isomers of 5 and 6-bromo-1-[(phenyl)sulfonyl]-2-[(4-nitrophenoxy)methyl]-1H-benzimidazoles as possible antimicrobial and antitubercular agents.

In this Letter, we report the structure-activity relationship (SAR) studies on series of positional isomers of 5(6)-bromo-1-[(phenyl)sulfonyl]-2-[(4-nitrophenoxy)methyl]-1H-benzimidazoles derivatives 7(a-j) and 8(a-j) synthesized in good yields and characterized by (1)H NMR, (13)C NMR and mass spectral analyses. The crystal structure of 7a was evidenced by X-ray diffraction study. The newly synthesized compounds were evaluated for their in vitro antibacterial activity against Staphylococcus aureus, (Gram-positive), Escherichia coli and Klebsiella pneumoniae (Gram-negative), antifungal activity against Candida albicans, Aspergillus flavus and Rhizopus sp. and antitubercular activity against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis, Mycobacterium fortuitum and MDR-TB strains. The synthesized compounds displayed interesting antimicrobial activity. The compounds 7b, 7e and 7h displayed significant activity against Mycobacterium tuberculosis H37Rv strain.

Synthesis and antimicrobial activity of 1,2,3-triazoles containing quinoline moiety

A new series of substituted 1,2,3-triazoles (4a-n) were synthesized from 4-azido-2,8-bistrifluoromethylquinoline 2. The 1,3-dipolar cycloaddition reaction of 2 with ethyl acetoacetate afforded 1-(2,8-Bistrifluoromethylquinolin-4-yl)-5-methyl-1,2,3-triazole-4-carboxylic acid 3, which was then converted into its corresponding acid hydrazide 3a. Condensation of this hydrazide with different aromatic aldehydes resulted in the formation of Schiff’s bases, N-[1-Arylmethylene]-1-[2,8-bistrifluoromethylquinoline-4-yl]-5-methyl-1H-1,2,3-triazole-4-carbohydrazides (4a-n). These newly synthesized 1,2,3-triazole derivatives were characterized by analytical and spectral data. All the synthesized compounds were evaluated in vitro for their antibacterial and antifungal activity. A brief investigation of the structure activity relationships revealed that the nature of the substituent on position 4 of the triazole ring influences the antimicrobial activity. Among the newly synthesized compounds, the most active compound was 4n, which contained the 3-methylthien-2-yl moiety and showed a broad spectrum of antimicrobial activity against all the strains used for testing. Compounds 4b, 4c, 4e, 4f, 4h and 4l showed significant antimicrobial activity at the concentration of 6.25 μg/mL.

Synthesis of Some Thiadiazolotriazinone Derivatives as Possible Antimicrobial Agents

A series of 7-substituted-3-t-butyl 4(H)-1,3,4-thiadiazolo(2,3-c)-1,2,4-triazine-4-one (3) have been synthesized by condensing 4-amino-6-t-butyl-3-mercapto-1,2,4-triazin-5(4H)-one (1) with substituted Arylfuroic acids (2) using POCl3 as a cyclizing agent. The newly synthesized compounds are characterized by elemental analysis, IR, 1H NMR, and mass spectral studies. The compounds were screened for their antibacterial and antifungal activities. Some of the compounds showed promising antibacterial and antifungal activity.

Synthesis of Some New 4-{2-[(Aryl)amino]-1,3-thiazol4-yl}benzene-1,2-diols as Possible Antibacterial and Antifungal Agents

Some new 4-{2-[(aryl) amino]-1,3-thiazol-4-yl}benzene-1,2-diols are prepared and characterized by spectral analysis. The newly prepared compounds are studied for their antibacterial and antifungal activity. Interestingly, almost all the compounds are found to possess promising antibacterial and antifungal activity against all tested microorganisms.

Protective Effect of Nardostachys jatamansi Against Radiation-induced Damage at Biochemical and Chromosomal Levels in Swiss Albino Mice

The effect of 100 mg of ethanol extract of Nardostachys jatamansi was studied on the mice exposed to 6 Gy electron beam radiation. Treatment of mice with 100 mg of Nardostachys jatamansi extract for 15 days before irradiation reduced the symptoms of radiation sickness when compared with the nondrug treated irradiated groups. The irradiation of animals resulted in an elevation in lipid peroxidation and reduction in glutathione, total antioxidants and antioxidant enzymes such as glutathione peroxidase and catalase activities. Irradiated group had shown micronucleus in the bone marrow cells. Treatment of mice with Nardostachys jatamansi extract before irradiation caused a significant depletion in lipid peroxidation followed by significant elevation in reduced glutathione, total antioxidants, glutathione peroxidase and catalase activity. It also showed a reduction in the micronucleus formation in the bone marrow cells. Our results indicate that the radioprotective activity of Nardostachys jatamansi extract may be due to free radical scavenging and increased antioxidant level in mice.