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Design and synthesis of novel series of 1,3,4-oxadiazoles containing FQs derivatives and screened their antibacterial, antimycobacterial properties. The synthesized compounds were characterized by different spectral techniques like IR, 1H NMR, 13C NMR, mass and elemental analysis. The results of the antimicrobial activity and compounds 6d, 6b, 6e, 6f and 6a demonstrated potent antibacterial activities with zone of inhibition of 42, 36, 37, 34 and 30 mm against S. aureus, E. faecalis, S. pneumoniae, E. coli and K. pneumoniae, respectively. 1,3,4-Oxadiazole derivatives 6a, 6b, 6 g were showed excellent antimycobacterial activity against M. smegmatis H37Rv with MICs 22.35, 16.20, 20.28 µg/mL, respectively. FQs 6d and 6b exhibited highest hydrogen bonding interactions with Asp83 (3.11 A˚), Ser80 (2.15 A˚) Asp27 (σ-σ), Arg87 (Π-Π), Arg87 (Π-Π), Ser80 (σ-σ), Ala84 (σ-σ) and binding energies ΔG = − 6.41, − 6.97 kcal/mol with active site of topoisomerase-IV from S. pneumoniae [4KPE]. We performed a computational investigation of compounds 6a–j for their absorption, distribution, metabolism and excretion (ADME) properties by using the Molinspiration, Molsoft toolkits. The ligands 6f, 6d and 6b reveal the highest pharmacokinetic properties and possess maximum drug-likeness model score 1.59, 1.46 and 1.23, respectively.

A series of new 1,3,4-oxadiazole derivatives bearing the 2-positioned 2,5-dimethoxyphenyl substituent and 5-positioned organylsulfanyl moiety were designed and synthesized. Screening for anticancer activity against an array of human cancer cells revealed the superior activity of 2-(2,5-dimethoxyphenyl)-5-propylthio-1,3,4-oxadiazole. 2-(2,5-Dimethoxyphenyl)-5-butylthio-1,3,4-oxadiazole displayed excellent activity against breast cancer cell lines.

Acridone based synthetic and natural products with inherent anticancer activity advancing the research and generating a large number of structurally diversified compounds. In this sequence we have designed, synthesized a series of tetracyclic acridones with amide framework viz., 3-(alkyloyl/ aryloyl/ heteroaryloyl/ heteroaryl)-2,3-dihydropyrazino[3,2,1-de]acridin-7(1H)-ones and screened for their in vitro anti-cancer activity. The in vitro study revealed that compounds with cyclopropyl-acetyl, benzoyl, p-hydroxybenzoyl, p-(trifluoromethyl)benzoyl, p-fluorobenzoyl, m-fluorobenzoyl, picolinoyl, 6-methylpicolinoyl and 3-nicotinoyl groups are active against HT29, MDAMB231 and HEK293T cancer cell lines. The molecular docking studies performed for them against 4N5Y, HT29 and 2VWD revealed the potential ligand–protein binding interactions among the neutral aminoacid of the enzymes and carbonyl groups of the title compounds with a binding energy ranging from − 8.1394 to − 6.9915 kcal/mol. In addition, the BSA protein binding assay performed for them has confirmed their interaction with target proteins through strong binding to BSA macromolecule. The additional studies like ADMET, QSAR, bioactivity scores, drug properties and toxicity risks ascertained them as newer drug candidates. This study had added a new collection of piperazino fused acridone derivatives to the existing array of other nitrogen heterocyclic fused acridone derivatives as anticancer agents. © 2020, The Author(s). The authors thank GVK Biosciences Pvt. Ltd., Nacharam, Hyderabad, India for sponsoring chemicals and analytical data. Authors Dr. Avula Vijaya Kumar Reddy and Prof. Dr. Grigory V. Zyryanov thank Ural Federal University for support and acknowledge the financial support of the Russian Science Foundation, Moscow, Russian Federation (RSF Grant No.: 18-13-00365). The corresponding author Dr. Visweswara Rao Pasupuleti thank Universiti Malaysia Sabah for the financial support.

A series of regioisomeric (2,5-dimethoxybenzoic acid, veratric acid) analogues were prepared by swapping the carboxylic motif to its oxadiazole bioisostere and have been screened for in vitro anticancer studies by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay. All of them were well characterized by spectroscopic techniques. Among the screened compounds, 9 i (2-(2,5-dimethoxyphenyl)-5-(5-phenylthiophen-2-yl)-1,3,4-oxadiazole) demonstrated superior activity against MDA231 cells. Products 9 i displayed excellent activity against DU145, HCT15 and 10 i (2-(3,4-dimethoxyphenyl)-5-(5-phenylthiophen-2-yl)-1,3,4-oxadiazole) against MDA231 cells. Structure of 10 c (2-(3,4-dimethoxyphenyl)-5-(2,4,6-trimethoxyphenyl)-1,3,4-oxadiazole) was further authenticated through single crystal X-ray diffraction. Analogue 9 i have come out to be the best anticancer and antimycobacterial agent.

A series of novel 1,2,3-triazole–etodolac hybrids (6a–l) were designed and synthesized as potent anti-cancer molecules. The synthesis strongly relied on Huisgen's 1,3-dipolar cycloaddition between etodolac azide 3 and substituted terminal alkynes 5a–l. The use of CH2Cl2 as a co-solvent with H2O increased the reaction rate and provided the corresponding 1,2,3-triazole–etodolac hybrids (6a–l) in excellent yields compared to other organic co-solvent systems. All the compounds were screened for their in vitro anticancer activity against human A549 cell lines and compounds 6e, 6f, 6h, 6j, and 6l were found to be the best anti-cancer molecules as compared to the marketed drug doxorubicin.

A series of new edaravone derivatives 3-7 have been synthesized, characterised using various spectroscopic techniques and screened for their in vitro anti-cancer, antioxidant activities. Structure of 5d was further substantiated through single crystal X-ray diffraction. Among the tested, 5l exhibited pronounced activity against PC3 cancer cells. Compounds 5i, 5l, 7c showed potent activity against A549 cancer cells. Products 5k, 6, 7c demonstrated good antioxidant activity with MIC values of 18.60, 16.27, 16.07μg/mL respectively. Further the reported analogues were also tested on normal HEK293T cells and displayed low to good safer profiles. Derivatives 5l and 7c have come out to be safer potent anticancer, antioxidant agents. Additionally, the target products were subjected to their molecular properties prediction and drug likeness by employing Molinspiration and Osiris property explorer toolkits. None of them violated Lipinski's boundaries classifying the title compounds as potential anticancer and antioxidant agents.

A facile and efficient method for the synthesis of novel derivatives of pefloxacin hydrazone via condensation of various aldehydes and pefloxacin acid hydrazide using conventional as well as solvent-free microwave irradiation methods was reported. The biological activity of these compounds was screened using array of techniques and found to exhibit promising broad spectrum of antibacterial activity against Gram-positive and Gram-negative bacteria, moderate antimycobacterial activity against Mycobacterium smegmatis and moderate antifungal activity opposed to Aspergillus clavatus and Candida albicans. Cytotoxic assay of the title compounds was evaluated against human Pc-3 cancer cell lines, and interestingly, very good anticancer properties were shown by the compounds. To explore the binding mode of the compounds and understand the key active site residues with Staphylococcusaureus DNA gyrase, a molecular docking study has been performed. The results of the docking studies of the reported derivatives were quite promising and manifested strong non-bonded interactions with DNA Gyrase.

We present a convenient route for the synthesis of C6-amino-C5’-N-cyclopropyl carboxamido-C2-alkynylated purine nucleoside analogues 11a-g via Sonogashira coupling reaction. The nine step synthesis is easy to perform, employing commercially available reagents. Compound 9 is used as key intermediate for the synthesis of analogues 11a-g. Synthetic intermediates and final products are appropriately characterized by IR, 1H NMR, 13C NMR and Mass. The modified nucleoside analogues 11a-g is evaluated for in vitro anticancer activity against MDA-MB-231 and Caco-2 cell lines. Screening data reveals that compounds 11b and 11e displayed potent IC50 value of 7.9, 6.8 µg/mL respectively against MDA-MB-231 and of 7.5, 8.3 µg/mL respectively against Caco-2 than the standard drug doxorubicin, thus establishing the potential anti-cancer properties of these newer derivatives.

A series of 2,5-disubstituted-1,3,4-thiadiazole derivatives 5a-5l, 7a-7e and 9 have been synthesised and screened for in vitro antimycobacterial activity against Mycobacterium smegmatis MC-155. In addition these compounds have also been screened for cytotoxic activity against cancer cell lines HT-29, MDA-MB-231 by MTT colorimetric assay. The compounds are well characterized by spectral analysis viz. (1)H NMR, (13)C NMR, FT-IR, mass and HRMS. Screening results indicate that compounds 5g, 7a possess good antitubercular activity with MIC value 65.74 and 40.86, respectively, compounds 5g, 7a, 7b, 7d, 7e and 9 displayed promising cytotoxic activity against the cell lines tested. 5g and 7a stand out to be potent antimycobacterial and anticancer agents among the tested series. Further the title compounds were also tested on human normal cells HEK293T and are found to be safer with lesser cytotoxicity. It is interesting to observe that compound 5g has come out to be safer, potent anticancer and antimycobacterial agent.