Faculty Publications
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Publications by NITK Faculty
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Item Regioselective reaction: Synthesis, characterization and pharmacological studies of some new Mannich bases derived from 1,2,4-triazoles(2009) Isloor, A.M.; Kalluraya, B.; Shetty, P.In the present investigation, a series of new 4[(3-substituted-1H-pyrazol-4-yl)methyleneamino]-5-substituted-2-[(4-methylpiperzine-1-yl)methyl]-2H-1,2,4-triazole-3(4H)-thiones (4) were synthesized by the aminomethylation of 4-(3-substituted-1H-pyrazol-3-yl)methyleneamino-5-substituted-4H-1,2,4-triazole-3-thiols (3) with formaldehyde and N-methylpiperzine. These newly synthesized Schiff and Mannich bases were characterized by IR, 1H NMR, mass spectral data and elemental analyses. These compounds were screened for their antibacterial and antifungal activity. Some of the compounds were found to exhibit significant antimicrobial activity. © 2009 Elsevier Masson SAS. All rights reserved.Item Synthesis, characterization and biological activity of some new 1,3,4-oxadiazole bearing 2-flouro-4-methoxy phenyl moiety(2010) Chandrakantha, B.; Shetty, P.; Nambiyar, V.; Isloor, N.; Isloor, A.M.In the present study a series of new 1,3,4-oxadiazole derivatives containing 2-fluoro-4-methoxy moiety were synthesized. These newly synthesized compounds were characterized by NMR, mass spectral, IR spectral study and also by C, H, N analyses. All the newly synthesized compounds were screened for their antibacterial and antifungal studies. Antimicrobial studies revealed that compounds 4a and 4b showed significant antibacterial activity against Escherichia coli and Pseudomonas aeruginosa Compound 4i showed significant antifungal activity against C. albicans. © 2009 Elsevier Masson SAS. All rights reserved.Item Novel chromeno [2,3-b]-pyrimidine derivatives as potential anti-microbial agents(2010) Sankappa Rai, U.; Isloor, A.M.; Shetty, P.; Vijesh, A.M.; Prabhu, N.; Isloor, S.; Thiageeswaran, M.; Fun, H.-K.An efficient, microwave irradiated synthesis of novel chromeno[2,3-b]-pyrimidine derivatives was carried out. 2-Amino-3,4-dihydro-2H-chromene-3-carbonitrile was converted into imine using N,N-Dimethylacetaldehyde dimethylacetal to give the core intermediate, which was used for the preparation of chromenopyrimidine library, using acetic acid and different amine in microwave irradiation for 5 min. Structures of newly synthesized compounds were confirmed by spectral studies. Compound 6g was characterized by single crystal X-ray analysis. All the compounds were also screened for their anti-microbial activity. Few of the compounds are found to be potential antimicrobials. © 2010 Elsevier Masson SAS. All rights reserved.Item Synthesis and biological evaluation of aminoketones(2010) Sankappa Rai, U.; Isloor, A.M.; Shetty, P.; Isloor, N.; Malladi, S.; Fun, H.-K.A three-component Mannich reaction of different ketones with aromatic aldehydes and different amines in microwave irradiation under solvent free condition afforded corresponding ?-amino carbonyl compounds in excellent yields. This method proved as a novel and improved modification of the reported three-component Mannich reaction in terms of milder reaction conditions, reaction times, clean reaction profiles, very small quantity of catalyst and simple workup procedure. Newly synthesized ?-aminoketones were characterized by spectral studies. Structure of compound 4a was also confirmed by single-crystal X-ray analysis. All the compounds were screened for their antimicrobial activity by MIC method. Few of the molecules were found to be biologically potent. © 2010 Elsevier Masson SAS. All rights reserved.Item Synthesis, characterization and in vitro cytotoxic properties of some new Schiff and Mannich bases in Hep G2 cells(Birkhauser Boston, 2011) Dhanya, D.; Isloor, A.M.; Shetty, P.; Chandrakantha, B.; Satyamoorthy, K.A series of 5-substituted-4-amino-3-mercapto- 1,2,4-triazoles were synthesized and were treated with various 3-substituted pyrazole aldehydes to obtain a series of new Schiff bases (3a-l). Few of the selected Schiff bases were converted into Mannich bases by reaction with diphenylamine/morpholine in presence of formaldehyde in ethanol media (4a-e, 5a-e). These newly synthesized compounds were characterized by elemental analysis, IR, NMR and mass spectrometry studies. A comparative study on the cytotoxic activities of few selected Schiff and Mannich bases was done in HepG2 cells using MTT assay. Few of the screened Schiff bases, 3a, 3d, 3e, 3g and 3h showed dose dependent cytotoxic activity, 3a being the most potent with an IC50 value of 0.018 g/l comparable to the standard drug doxorubicin. Among the Mannich bases, 5b was the most active with an IC50 value of 0.034 g/l. The Schiff bases were found to be more active, when compared to Mannich bases derived from them. The morpholine derived Mannich bases were more potent than those obtained from diphenyl amine. © Springer Science+Business Media, LLC 2010.Item Synthesis, characterization, antioxidant, and anticancer studies of 6-[3-(4-chlorophenyl)-1H-pyrazol-4-yl]-3-[(2-naphthyloxy) methyl][1,2,4] triazolo[3,4-b][1,3,4]thiadiazole in HepG2 cell lines(2011) Dhanya, D.; Isloor, A.M.; Shetty, P.; Satyamoorthy, K.; Prasad, A.S.B.Triazolo- thiadiazoles exhibit a variety of pharmacological properties, due to their cytotoxicity. In continuation of a previous study on triazolo-thiadiazoles, the authors have synthesized a new thiadiazole, 6-[3-(4-chlorophenyl)- 1-H-pyrazol-4-yl]-3-[(2-naphthyloxy)methyl] [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole (CPNT), which was further characterized by advanced spectral techniques and elemental analysis. The compound exhibited a dose-dependent cytotoxic effect on hepatocellular carcinoma cell line, HepG2 with very low IC50 value of 0.8 ?g/ml in 24 h when compared with standard drug, doxorubicin. Incorporation of [3H] thymidine in conjunction with cell cycle analysis suggested that CPNT inhibited the growth of HepG2 cells. Flow cytometric studies revealed more percentage of cells in subG1 phase, indicating apoptosis, which was further confirmed through chromatin condensation studies by Hoechst staining. In vitro antioxidant activity of CPNT was determined by DPPH and ABTS free radical scavenging assays which revealed increasing scavenging activity with increasing concentration of the compound when compared with reference ascorbic acid. © Springer Science+Business Media, LLC 2010.Item A novel series of homoallylic amines as potential antimicrobials(2012) Rai, U.S.; Isloor, A.M.; Shetty, P.; Isloor, N.; Padaki, M.; Fun, H.-K.An efficient catalytic three-component reaction of aldehydes, amines, and allyltributylstannate has been successfully developed to produce homoallylic amines at 25°C, in excellent yields, in the presence of 1 mol% of trifluoroacetic acid an inexpensive and environmentally friendly catalyst. Newly synthesized compounds were confirmed by spectral studies. Compound 3o was characterized by single crystal X-ray analysis. All the compounds were also screened for their antimicrobial activity. Halogen-substituted compounds namely 3d, 3g, 3n, and 3o have showed excellent antibacterial activity. © Springer Science+Business Media, LLC 2011.Item Synthesis, characterization and antimicrobial activity of novel ethyl 1-(N-substituted)-5-phenyl-1H-pyrazole-4-carboxylate derivatives(2012) Chandrakantha, B.; Isloor, A.M.; Shetty, P.; Isloor, S.; Malladi, S.; Fun, H.-K.In the present study, a novel series of Pyrazole derivatives (3a-m) were synthesized by condensing ethyl-3-(dimethylamino)-2-(phenylcarbonyl)prop-2- enoate with different aromatic and aliphatic hydrazines. These newly synthesized compounds were characterized by NMR, mass spectral, IR spectral studies as well as by C, H, and N analyses. All the newly synthesized compounds were screened for their antibacterial properties against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. Among the screened samples, 3c, 3f, 3k, and 3l have showed excellent antibacterial activity against all the tested bacterial strains as compared to the standard drug Ceftriaxone. Few of the compounds were found to be biologically potent. Molecular structure of compound 3i was confirmed by single crystal X-ray analysis. © Springer Science+Business Media, LLC 2011.Item Synthesis and anti-inflammatory evaluation of some new 3,6-disubstituted-1, 2,4-triazolo-[3,4-b]-1,3,4-thiadiazoles bearing pyrazole moiety(2012) Malladi, S.; Isloor, A.M.; Shetty, P.; Fun, H.-K.; Telkar, S.; Mahmood, R.; Isloor, N.In the present study, a new series of 3,6-disubstituted- 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazoles (4aj) have been synthesized by condensing 3-substituted-4-amino-5- mercapto-1,2,4-triazoles (1a-b) with various 3-substitutedpyrazole- 4-carboxylic acids (3a-e) in the presence ofPOCl3. The structures of newly synthesized compounds were characterized by elemental analysis, IR, 1H NMR, 13CNMR, and mass spectroscopic studies. Structure of the compound 4b was also confirmed by recording the single crystal X-ray structure. All the synthesized compounds were screened for their anti-inflammatory activities by carrageenan induced paw edema method. Anti-inflammatory screening indicated that, compounds 4d, 4e, and 4h were found to be biologically active whereas remaining compounds showed poor antiinflammatory activity. Also molecular docking studies were also performed for compounds which showed good antiinflammatory activity. © Springer Science+Business Media, LLC 2011.Item T3P mediated synthesis of some new quinoline substituted pyrazole derivatives and its antibacterial studies(2012) Chandrakantha, B.; Isloor, A.M.; Peethambar, S.K.; Shetty, P.A series of new N-(substituted)-5-phenyl-1-(quinolin-2-yl)-1H-pyrazole-4-carboxamide derivatives (5a-h) have been synthesized by condensing ethyl-3-(dimethylamino)-2-[(phenyl)carbonyl]prop-2-enoate 2 with quinoline-2-yl-hydrazine. Compound 3 is hydrolyzed into 4 which is upon further coupled with different aromatic/aliphatic amines using 50% prpopyl phosphonic anhydride (T3P) in ethyl acetate as coupling reagent to afford different quinoline substituted pyrazole carboxamide derivatives. All the newly synthesized compounds were screened for their invitro antibacterial studies against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The results revealed that compounds 5d, 5f, and 5h showed good antibacterial activity towards all bacterial strains. These newly synthesized compounds were characterized by NMR, mass spectral, IR spectral study and also by C, H, N analyses.