Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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Item Hantzsch reaction: Synthesis and characterization of some new 1,4-dihydropyridine derivatives as potent antimicrobial and antioxidant agents(2011) Vijesh, A.M.; Isloor, A.M.; Peethambar, S.K.; Shivananda, K.N.; Arulmoli, T.; Isloor, N.In the present study two new series of Hantzsch 1,4-dihydropyridine derivatives (1,4-DHPs) containing substituted pyrazole moiety (4a-f and 5a-f) were synthesized by the reaction of 3-aryl-1H-pyrazole-4-carbaldehydes with 1,3-dicarbonylcompounds (ethylacetoacetate and methylacetoacetate) and ammonium acetate. The newly synthesized compounds were characterized by IR, NMR, mass spectral study and also by C, H, N analyses. New compounds were screened for their antimicrobial activity by well plate method (zone of inhibition). Antioxidant studies of the synthesized compounds were also performed by measuring the DPPH radical scavenging assay. Compounds 4c, 4e and 4f were found to be potent antibacterial and antioxidant agents. The acute oral toxicity study for the compounds 4c, 4e and 4f were carried out and the experimental studies revealed that compounds 4c and 4e is safe up to 3000 mg/kg and no death of animals were recorded. However in compound 4f, we found mortality above 2000 mg and also significant behavioral changes in experimental animals. © 2011 Elsevier Masson SAS. All rights reserved.Item Synthesis and evaluation of antioxidant, antimicrobial activities of new 2,4-disubstituted thiazoles(2012) Malladi, S.; Isloor, A.M.; Peethambar, S.K.; Shivananda, K.N.A new series of 2,4-disubstituted thiazole derivatives were synthesized by the reaction of various 3-aryl-1H-pyrazole-4- carbaldehyde thiosemicarbazones (2a-e) and phenacyl bromides. The compounds (3a-n) were characterized by IR, NMR, mass spectra and C, H, N analyses. All the synthesized compounds were screened for their antioxidant and antimicrobial activities. Antioxidant studies revealed that, compounds 3b, 3j and 3n showed significant scavenging activity whereas compounds 3e and 3n exhibited significant antimicrobial activity. The acute oral toxicity study for the compound 3e and 3n have revealed good safety profile till the uppermost dose (2000 mg/kg).Item Synthesis and biological evaluation of new imidazo[2,1-b][1,3,4]thiadiazole-benzimidazole derivatives(Elsevier Masson SAS infos@masson.fr 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2015) Ramprasad, J.; Nayak, N.; Udayakumar, U.; Yogeeswari, P.; Sriram, D.; Peethambar, S.K.; Achur, R.; Santosh Kumar, H.S.S.In this report, we describe the synthesis and biological evaluation of a new series of 2-(imidazo[2,1-b][1,3,4]thiadiazol-5-yl)-1H-benzimidazole derivatives (5a-ac). The molecules were analyzed by 1H NMR, 13C NMR, mass spectral and elemental data. The structure of one of the pre-final compounds, 6-(4-methoxyphenyl)-2-(4-methylphenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (4d) and that of a target compound, 2-[2-methyl-6-(4-methyl phenyl) imidazo[2,1-b][1,3,4]thiadiazol-5-yl]-1H-benzimidazole (5aa) were confirmed by single crystal XRD studies. All the target compounds were screened for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Seven (5c, 5d, 5l, 5p, 5r, 5z and 5aa) out of twenty nine compounds showed potent anti-tubercular activity with a MIC of 3.125 ?g/mL. A p-substituted phenyl group (p-tolyl or p-chlorophenyl) in the imidazo[2,1-b][1,3,4]thiadiazole ring and/or a chloro group in the benzimidazole ring enhance anti-tuberculosis activity whereas a nitro group in the benzimidazole ring reduces the activity. In the antibacterial screening, compounds 5i, 5w and 5ac showed promising activity against the tested bacterial strains. Further, antifungal and antioxidant activities of these molecules were also investigated. In the cytotoxicity study, the active antitubercular compounds exhibited very low toxicity against a normal cell line. © 2015 Elsevier Masson SAS.