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TATAR, ESRA

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2013 - 201932020 - 20211
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Subject: NONNUCLEOSIDE INHIBITORS ×

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Now showing 1 - 5 of 5
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    PublicationOpen Access
    Design, Synthesis, and Molecular Docking Studies of a Conjugated-Thiadiazole Thiourea Scaffold as Antituberculosis Agents
    (PHARMACEUTICAL SOC JAPAN, 2016) TATAR, ESRA; Tatar, Esra; Karakus, Sevgi; Kucukguzel, Sukriye Guniz; Okullu, Sinem Oktem; Unubol, Nihan; Kocagoz, Tanil; De Clercq, Erik; Andrei, Graciela; Snoeck, Robert; Pannecouque, Christophe; Kalayci, Sadik; Sahin, Fikrettin; Sriram, Dharmarajan; Yogeeswari, Perumal; Kucukguzel, Ilkay
    In view of the emergence and frequency of multidrug-resistant and extensively drug-resistant tuberculosis and consequences of acquired resistance to clinically used drugs, we undertook the design and synthesis of novel prototypes that possess the advantage of the two pharmacophores of thiourea and 1,3,4-thiadiazole in a single molecular backbone. Three compounds from our series were distinguished from the others by their promising activity profiles against Mycobacterium tuberculosis strain H(37)Rv. Compounds 11 and 19 were the most active representatives with minimum inhibitory concentration (MIC) values of 10.96 and 11.48 mu m, respectively. Compound 15 was shown to inhibit M. tuberculosis strain H(37)Rv with an MIC value of 17.81 mu m. Cytotoxicity results in the Vero cell line showed that these three derivatives had selectivity indices between 1.8 and 8.7. In order to rationalize the biological results of our compounds, molecular docking studies with the enoyl acyl carrier protein reductase (InhA) of M. tuberculosis were performed and compounds 11, 15, and 19 were found to have good docking scores in the range of -7.12 to -7.83 kcal/mol.
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    Synthesis and evaluation of novel 1,3,4-thiadiazole-fluoroquinolone hybrids as antibacterial, antituberculosis, and anticancer agents
    (SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2018) TÜRE, ASLI; Demirci, Asli; Karayel, Kaan Gokce; Tatar, Esra; Oktem Okullu, Sinem; Unubol, Nihan; Tasli, Pakize Neslihan; Kocagoz, Zuhtu Tanil; Sahin, Fikrettin; Kucukguzel, Ilkay
    A series of 5-substituted-1,3,4-thiadiazole-based fluoroquinolone derivatives were designed as potential antibacterial and anticancer agents using a molecular hybridization approach. The target compounds 16-25 were synthesized by reacting the corresponding N-(5-substituted-1,3,4-thiadiazol-2-yl)-2-chloroacetamides with ciprofloxacin or norfloxacin. The purity and identity of the synthesized compounds were determined by the use of chromatographic and spectral techniques (NMR, IR, MS, etc.) besides elemental analysis. Antibacterial, antituberculosis, and anticancer activity of the target compounds were evaluated against selected strains and cancer cell lines. Compound 20 was appreciated as the most active agent representing antibacterial activity against Escherichia coli and Staphylococcus aureus with MIC values of 4 mu g/mL and 2 mu g/mL, respectively. Amongst the synthesized fluoroquinolone derivatives, compounds 19 and 20 were found to have modest antitubercular activity with 8 mu g/mL MIC values for each. Most potent derivative, compound 20 was docked against Staphylococcus aureus and Mycobacterium tuberculosis DNA gyrase enzymes to visualize the possible conformation of the compound. Additionally, anticancer activities of target compounds were evaluated on seven different cancer cell lines.
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    Some Hydrazones of 2-Aroylamino-3-methylbutanohydrazide: Synthesis, Molecular Modeling Studies, and Identification as Stereoselective Inhibitors of HIV-1
    (WILEY-V C H VERLAG GMBH, 2013) TATAR, ESRA; Tatar, Esra; Kucukguzel, Ilkay; Daelemans, Dirk; Talele, Tanaji T.; Kaushik-Basu, Neerja; De Clercq, Erik; Pannecouque, Christophe
    In accordance with our antiviral drug development attempt, acylhydrazone derivatives bearing amino acid side chains were synthesized for the evaluation of their antiviral activity against various types of viruses. Among these compounds, 8S, 11S, and 12S showed anti-HIV-1 activity with a 50% inhibitory concentration (IC50)=123.8 mu M (selectivity index, SI>3), IC50=12.1 mu M (SI>29), IC50=17.4 mu M (SI>19), respectively. Enantiomers 8R, 11R, and 12R were inactive against the HIV-1 strain IIIB. Hydrazones 8S, 11S, and 12S which were active against HIV-1 wild type showed no inhibition against a double mutant NNRTI-resistant strain (K103N;Y181C). Molecular docking calculations of R- and S-enantiomers of 8, 11, and 12 were performed using the hydrazone-bound novel site of HIV-1 RT.
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    PublicationOpen Access
    Synthesis, characterization and biological evaluation of 1,3-thiazolidine-4-ones derived from (2S)-2-benzoylamino-3-methylbutanohydrazide hydrazones
    (MARMARA UNIV, 2021) TATAR, ESRA; Tatar, Esra; Kucukguzel, Ilkay; Otuk, Gulten; Bilgin, Merve; De Clercq, Erik; Andrei, Graciela; Snoeck, Robert; Pannecouque, Christophe; Kaushik-Basu, Neerja
    Novel 2-aryl-5-non-substituted / methyl-1,3-thiazolidine-4-one derivatives 14-33 carrying L-valine core were synthesized by the reaction of acylhydrazones 4-13 with thioglycolic acid / thiolactic acid. Structures of all synthesized compounds 14-33 were confirmed by IR, H-1-NMR and HR-MS analysis and C-13-NMR were recorded for selected compounds 17, 21, 28 and 30. None of the compounds 14-33 showed activity against HIV-1 (strain IIIB) or HIV-2 (strain ROD) in an MT-4/MTT based assay. Compounds 14-33 were also screened against Feline Corona Virus (FIPV), Feline Herpes Virus, HSV-1(KOS), HSV-1 (TK-KOS ACVr), HSV-2 (G), Vaccinia virus, Vesicular stomatitis virus, Cytomegalovirus, Varicella-Zoster virus, Respiratory syncytial virus, Coxsackie B4 virus, Parainfluenza-3 virus, Reovirus-1, Sindbis virus and Punta Toro virus, but none of them showed antiviral activity at subtoxic concentrations. Anti-HCV NS5B RdRp activity of some selected compounds from the series 14-33 were found to vary between 4.1-27 % at the concentration of 100 mu M. In vitro antibacterial activity evaluation of selected compounds 16-23 and 25-32, against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae ATCC 4352, Bacillus subtilis ATCC 6633, Staphylococcus epidermidis ATCC 12228, MRSA and antifungal activity against Candida albicans ATCC 10231 resulted in the MIC values between 625->5000 mu g/ml.
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    Synthesis and structure-activity relationship of L-methionine-coupled 1,3,4-thiadiazole derivatives with activity against influenza virus
    (WILEY) TATAR, ESRA; Tatar, Esra; Yaldiz, Seda; Kulabas, Necla; Vanderlinden, Evelien; Naesens, Lieve; Kucukguzel, Ilkay
    In previous investigations, we identified a class of 1,3,4-thiadiazole derivatives with antiviral activity. N-{3-(Methylsulfanyl)-1-[5-(phenylamino)-1,3,4-thiadiazole-2-yl]propyl}benzamide emerged as a relevant lead compound for designing novel influenza A virus inhibitors. In the present study, we elaborated on this initial lead by performing chemical synthesis and antiviral evaluation of a series of structural analogues. During this research, thirteen novel 1,3,4-thiadiazole derivatives were synthesized by the cyclization of the corresponding thiosemicarbazides as synthetic precursors. The structures and the purities of the synthesized compounds were confirmed through chromatographic and spectral data. Four L-methionine-based 1,3,4-thiadiazole derivatives displayed activity against influenza A virus, the two best compounds being 24 carrying a 5-(4-chlorophenylamino)-1,3,4-thiadiazole moiety and 30 possessing a 5-(benzoylamino)-1,3,4-thiadiazole structure [antiviral EC50 against influenza A/H3N2 virus: 4.8 and 7.4 mu M, respectively]. The 1,3,4-thiadiazole derivatives were inactive against influenza B virus and a wide panel of unrelated DNA and RNA viruses. Compound 24 represents a new class of selective influenza A virus inhibitors acting during the virus entry process, as evidenced by our findings in a time-of-addition assay. Molecular descriptors and in silico prediction of ADMET properties of the active compounds were calculated. According to in silico ADMET and drug similarity studies, active compounds have been estimated to be good candidates for oral administration with no apparent toxicity considerations.