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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.Item One-pot synthesis of new triazole - Imidazo[2,1-b][1,3,4]thiadiazole hybrids via click chemistry and evaluation of their antitubercular activity(Elsevier Ltd, 2015) Ramprasad, J.; Nayak, N.; Udayakumar, U.; Yogeeswari, P.; Sriram, D.A new series of triazole-imidazo[2,1-b][1,3,4]thiadiazole hybrids (6a-s, 7a) were designed by a molecular hybridisation approach and the target molecules were synthesized via one pot click chemistry protocol. All the intermediates and final molecules were characterised using spectral methods and one of the target compounds (6c) was analysed by the single crystal XRD study. The derivatives were screened for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain. Two compounds, 6f and 6n, demonstrated significant growth inhibitory activity against the bacterial strain with a MIC of 3.125 ?g/mL. The presence of chloro substituent on the imidazo[2,1-b][1,3,4]thiadiazole ring and ethyl, benzyl or cyanomethylene groups on the 1,2,3-triazole ring enhance the inhibition activity of the molecules. The active compounds are not toxic to a normal cell line which signifies the lack of general cellular toxicity of these compounds. © 2015 Elsevier Ltd. All rights reserved.Item Synthesis of novel 5-[(1,2,3-triazol-4-yl)methyl]-1-methyl-3H-pyridazino[4,5-b]indol-4-one derivatives by click reaction and exploration of their anticancer activity(Birkhauser Boston, 2016) Panathur, N.; Gokhale, N.; Udayakumar, U.; Koushik, P.V.; Yogeeswari, P.; Sriram, D.A series of pyridazino[4,5-b]indole derivatives containing alkyl-, benzyl- and phenacyl-substituted 1,2,3-triazolylmethyl units was synthesized using click chemistry approach. All 30 compounds of the series were screened in vitro against four cancer cell lines, viz. breast cancer cells MDA-MB-231 and MCF 7, human primary glioblastoma U-87 and human neuroblastoma IMR-32 cell lines. Most of the compounds exhibited potent cancer cell growth inhibition activity at very low micromolar concentrations. The IC50 value of compounds 7v and 7x against human neuroblastoma IMR-32 cell line is 0.07 and 0.04 ?M, respectively. Among the tested compounds, ten compounds showed IC50 value less than 1 ?M against MDA-MB-231 cells, whereas against IMR-32 cells, nine compounds and, against U-87 cells, six compounds showed similar inhibition activity. Further, these molecules exhibited prominent binding affinity and docking scores in the molecular simulation study with the target enzyme PI3 kinase. Graphical Abstract: This paper illustrates the synthesis of new fused indole-pyridazinone derivatives containing substituted 1,2,3-triazoles via click chemistry approach. Most of the compounds exhibited potent cancer cell growth inhibition activity at very low micromolar concentrations. [Figure not available: see fulltext.] © 2015 Springer Science+Business Media New York.Item Structural modification of zolpidem led to potent antimicrobial activity in imidazo[1,2-: A] pyridine/pyrimidine-1,2,3-triazoles(Royal Society of Chemistry, 2019) Reddyrajula, R.; Udayakumar, U.Ambien (zolpidem), an imidazo[1,2-a]pyridine derivative, is a commercial drug to treat insomnia which also possesses antitubercular activity against Mycobacterium tuberculosis H37Rv. In this paper, we describe the synthesis of three diverse lead series of imidazo[1,2-a]pyridine/pyrimidine-1,2,3-triazoles (IPTs) which are designed by specific structural modifications of zolpidem. Most of the IPTs exhibited remarkable in vitro antitubercular activity with an MIC of 1.56 ?g mL-1, which is two-fold higher than the MIC of zolpidem. Further, the synthesized IPTs displayed moderate inhibitory activity against several bacterial and fungal strains as well, and also showed an acceptable safety profile as verified through in vitro cytotoxicity assessment against Vero cells. In addition, the potent IPTs exhibited promising binding interactions within the active site of the InhA enzyme. An interesting correlation between the in vitro inhibitory activity and the binding mode was observed: most of the potent molecules (MIC = 1.56 ?g mL-1) interact through a H-bond with the Tyr 158 residue of the target enzyme. These efforts toward the structural modification of zolpidem could be helpful for further optimization of the IPT core to develop new anti-TB drugs. This journal is © 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.Item Noncovalent inhibitors of DprE1 for tuberculosis treatment: design, synthesis, characterization, in vitro and in silico studies of 4-oxo-1,4-dihydroquinazolinylpyrazine-2-carboxamides(Taylor and Francis Ltd., 2025) Naik, S.; Dinesha, P.; Udayakumar, U.In this study, we present a novel series of 4-oxo-1,4-dihydroquinazolinylpyrazine-2-carboxamide derivatives, which exert their inhibitory effect on decaprenylphosphoryl-?-D-ribose 2’-epimerase (DprE1) via the establishment of non-covalent interactions with the pivotal Cys387 residue located within the enzyme’s active site. These compounds underwent scrutiny for their efficacy in combatting the Mycobacterium tuberculosis H37Rv strain, and compounds T8 and T13 exhibited promising antitubercular activity, boasting a minimal inhibitory concentration (MIC) of 7.99 and 8.27 µM respectively. Additionally, three compounds, T2, T3 and T12, showcased substantial antibacterial activity whereas compounds T12 and T13 exhibited pronounced antifungal efficacy. Remarkably, all active compounds demonstrated negligible cytotoxicity, and none posed harm to normal cells. To attain a more profound comprehension of the attributes of these compounds, we conducted in silico investigations to evaluate their Absorption, Distribution, Metabolism and Excretion properties. Additionally, molecular docking analyses were executed to elucidate their interactions with the DprE1 enzyme. Finally, Density Functional Theory studies were leveraged to explore the electronic characteristics of these compounds, thereby providing insights into their potential utility in the realm of pharmaceuticals. © 2024 Informa UK Limited, trading as Taylor & Francis Group.