- Crystal structure analysis and quantum chemical study of two macrocyclic compounds
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The synthesis of new organic macrocyclic nonlinear optical materials with good performance has taken the prime focus of research due to the unlimited design possibilities. Two macrocyclic structures, confirmed by 1H, 13C NMR and FT-IR, namely spiro pyrrolidine grafted methyl macrocycle C28H26N2O3 and 1,2,3 triazole bridged pyrrolidine grafted chloro macrocycle C29H27Cl1N4O30.5(H2O) are analysed by single crystal X-ray diffraction method. The UV–Vis spectra of the two compounds show that these crystals are transparent in the entire visible region. The global reactivity descriptors such as ionization potential, electron affinity, electronegativity, chemical hardness, chemical potential, chemical softness, electrophilicity index and nonlinear optical parameters such as dipole moment (μ) and static second order hyperpolarizability (γ) are determined in gas phase at the molecular level by semiempirical quantum chemical method with the coordinates obtained from X-ray diffraction as the starting geometry. In addition, the bioactivity scores were calculated from the chemical skeleton.
- Maragatham,Prabhakaran,Rajakumar,Lakshmi
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- Water stable fluorescent organotin(iv) compounds: aggregation induced emission enhancement and recognition of lead ions in an aqueous system
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Herein, synthesis, spectroscopic studies, single-crystal X-ray diffraction, aggregation-induced emission enhancement (AIEE) and sensing application of water-stable organotin(iv) compounds (4a-6aand4b-6b) obtained from 3-hydroxy-4H-chromen-4-one ligands are reported. All the synthesized organotin(iv) compounds were characterized using elemental analysis, FT-IR spectroscopy, multi-nuclei NMR (1H,13C, and119Sn) spectroscopy, UV-VIS, fluorescence spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. The119Sn NMR signal of compounds in the range ofδ?144.92 to ?190.68 ppm indicated the formation of hexacoordinated organotin species. The spectroscopic and single-crystal X-ray diffraction studies confirmed the formation of [L2SnR2] type compounds (where L is the bidentate ligand and R is an alkyl group) with a ‘skew-trapezoidal bipyramidal’ geometry. Furthermore, DFT calculations of compound4bbased on the DGDZVP basis set fully supported the stability of the structure where two short bonds Sn-O(C-O)acquire thecisposition rather than thetransposition. Single-crystal X-ray diffraction analysis of the crystals grown in the presence of water confirmed the stability of4ain water. Moreover, the water stability of a test compound4awas established by119Sn NMR data and spectrofluorimetric data. The spectrofluorimetric scan at different time intervals revealed the stability and constant emission response up to 24 h. The compounds were found to be fluorescent and exhibited aggregation-induced emission enhancement in MeOH/H2O mixtures, which was confirmed by HRTEM analysis. The test compound4ashowed selective spectrofluorimetric recognition of Pb2+ions in an aqueous medium by displaying an enhanced emission signal at 478 nm and enabled detection up to 22.66 μM. A mechanism of interaction is also proposed by spectroscopic experiments, spectrofluorimetric experiments and computational studies.
- Capalash, Neena,Kaur, Kulwinder,Kaur, Varinder,Singh, Raghubir
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p. 148 - 161
(2021/12/31)
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- Flavone-based hydrazones as new tyrosinase inhibitors: Synthetic imines with emerging biological potential, SAR, molecular docking and drug-likeness studies
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Targeting tyrosinase (TYR), a key enzyme responsible for melanogenesis disorders, is a well-known approach utilized for the development of melanogenesis inhibitor. A variety of dermatological disorders and microbial skin infections can cause hyperpigmentation. Hence, exploring new scaffolds for the treatment of melanogenesis disease is an inspiring goal. In this context, a series of varyingly substituted flavone-based hydrazones have been designed, synthesized and characterized successfully. The present study describes the discovery of novel mushroom tyrosinase inhibitors (TIs) for treating hyperpigmentation. In due course, flavone scaffold has been incorporated into the novel chemotypes that exhibit in vitro inhibitory effects against mushroom tyrosinase for the purpose of discovering anti‐melanogenic agents. Biological investigations of prepared analogs herein demonstrated moderate to excellent activity against most of the fungal-bacterial strains and their activity is comparable to those of commercially available antibiotics i.e., Ciprofloxacin and Ketoconazole. Based on in vitro tyrosinase inhibitory assay, some compounds exhibited potent inhibition particularly, 3g (IC50 = 1.40 ± 0.16 μM), 3j (IC50 = 0.95 ± 0.07 μM), 3o (IC50 = 1.13 ± 0.11 μM), and 3q (IC50 = 1.01 ± 0.1 μM) showed best inhibition i.e., 0.7, 0.5, 0.6 and 0.5 folds, respectively, than kojic acid (IC50 = 1.79 ± 0.6 μM). Lineweaver-Burk plots demonstrated that the most potential derivative 3j tyrosinase inhibition proceeds via non-competitive pathway and the Michaelis-Menton constant (Km) value is 0.0265. Molecular modeling was performed for all tested analogs (3a–3q) using a model of mushroom tyrosinase to find crucial binding modes liable for inhibitory activity. The SARs were preliminarily examined, and the docking study revealed that analogs 3j, 3o and 3p had a strong binding association to tyrosinase (2Y9X). Furthermore, a drug-likeness study was employed and confirmed the favorable activity of the new analogs as a new anti-tyrosinase agent.
- Alsantali, Reem?I.,Mughal, Ehsan?Ullah,Naeem, Nafeesa,Alsharif, Meshari?A.,Sadiq, Amina,Ali, Anser,Jassas, Rabab.?S.,Javed, Qamar,Javid, Asif,Sumrra, Sajjad Hussain,Alsimaree, Abdulrahman?A.,Zafar, Muhammad?Naveed,Asghar, Basim?H.,Altass, Hatem?M.,Moussa, Ziad,Ahmed, Saleh?A.
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- Mycobactin Analogues with Excellent Pharmacokinetic Profile Demonstrate Potent Antitubercular Specific Activity and Exceptional Efflux Pump Inhibition
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In this study, we have designed and synthesized pyrazoline analogues that partially mimic the structure of mycobactin, to address the requirement of novel therapeutics to tackle the emerging global challenge of antimicrobial resistance (AMR). Our investigation resulted in the identification of novel lead compounds 44 and 49 as potential mycobactin biosynthesis inhibitors against mycobacteria. Moreover, candidates efficiently eradicated intracellularly surviving mycobacteria. Thermofluorimetric analysis and molecular dynamics simulations suggested that compounds 44 and 49 bind to salicyl-AMP ligase (MbtA), a key enzyme in the mycobactin biosynthetic pathway. To the best of our knowledge, these are the first rationally designed mycobactin inhibitors to demonstrate an excellent in vivo pharmacokinetic profile. In addition, these compounds also exhibited more potent whole-cell efflux pump inhibition than known efflux pump inhibitors verapamil and chlorpromazine. Results from this study pave the way for the development of 3-(2-hydroxyphenyl)-5-(aryl)-pyrazolines as a new weapon against superbug-associated AMR challenges.
- Shyam, Mousumi,Verma, Harshita,Bhattacharje, Gourab,Mukherjee, Piyali,Singh, Samsher,Kamilya, Sujit,Jalani, Pushpendu,Das, Swetarka,Dasgupta, Arunava,Mondal, Abhishake,Das, Amit Kumar,Singh, Amit,Brucoli, Federico,Bagnéris, Claire,Dickman, Rachael,Basavanakatti, Vinay N.,Naresh Babu, Patibandla,Sankaran, Vadivelan,Dev, Abhimanyu,Sinha, Barij Nayan,Bhakta, Sanjib,Jayaprakash, Venkatesan
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p. 234 - 256
(2022/01/20)
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- Exploring 3-hydroxyflavone scaffolds as mushroom tyrosinase inhibitors: synthesis, X-ray crystallography, antimicrobial, fluorescence behaviour, structure-activity relationship and molecular modelling studies
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To explore new scaffolds as tyrosinase enzyme inhibitors remain an interesting goal in the drug discovery and development. In due course and our approach to synthesize bioactive compounds, a series of varyingly substituted 3-hydroxyflavone derivatives (1-23) were synthesized in one-pot reaction and screened for in?vitro against mushroom tyrosinase enzyme. The structures of newly synthesized compounds were unambiguously corroborated by usual spectroscopic techniques (FTIR, UV-Vis, 1H-, 13C-NMR) and mass spectrometry (EI-MS). The structure of compound 15 was also characterized by X-ray diffraction analysis. Furthermore, the synthesized compounds (1-23) were evaluated for their antimicrobial potential. Biological studies exhibit pretty good activity against most of the bacterial-fungal strains and their activity is comparable to those of commercially available antibiotics i.e. Cefixime and Clotrimazole. Amongst the series, the compounds 2, 4, 5, 6, 7, 10, 11, 14 and 22 exhibited excellent inhibitory activity against tyrosinase, even better than standard compound. Remarkably, the compound 2 (IC50 = 0.280 ± 0.010 μg/ml) was found almost sixfold and derivative 5 (IC50 = 0.230 ± 0.020 μg/ml) about sevenfold more active as compared to standard Kojic acid (IC50 =1.79 ± 0.6 μg/ml). Moreover, these synthetic compounds (1-23) displayed good to moderate activities against tested bacterial and fungal strains. Their emission behavior was also investigated in order to know their potential as fluorescent probes. The molecular modelling simulations were also performed to explore their binding interactions with active sites of the tyrosinase enzyme. Limited structure-activity relationship was established to design and develop new tyrosinase inhibitors by employing 2-arylchromone as a structural core in the future. Communicated by Ramaswamy H. Sarma.
- Ashraf, Jamshaid,Mughal, Ehsan Ullah,Sadiq, Amina,Bibi, Maryam,Naeem, Nafeesa,Ali, Anser,Massadaq, Anam,Fatima, Nighat,Javid, Asif,Zafar, Muhammad Naveed,Khan, Bilal Ahmad,Nazar, Muhammad Faizan,Mumtaz, Amara,Tahir, Muhammad Nawaz,Mirzaei, Masoud
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p. 7107 - 7122
(2020/08/21)
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- Synthesis, spectral and sol-gel behavior of mixed ligand complexes of titanium(iv) with oxygen, nitrogen and sulfur donor ligands
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A new route to synthesize nano-sized Ti(IV) mixed ligand complexes have been investigated by the reaction of titanium(IV) chloride with ammonium salts of dithiophosphate and 3(2'-hydroxyphenyl)-5-(4- substituted phenyl) pyrazolines. The resultant complex is then treated with H2S gas to get sulfur bridged dimer of Ti(IV) complex, a precursor of TiS2. The morphology of the complexes was studied by employing XRD which shows that all the complexes are amorphous solid. Molecular weight measurements, elemental analysis in conjugation with spectroscopic (IR, 1H NMR, 13C NMR and 31P NMR) studies revealed the dimeric nature of the complexes in which pyrazoline and dithiophosphate are bidentate. Scanning electron microscopic image and XRD indicate that the particles are in the nano range (50 nm). Putting all the facts together, coordination number six is proposed for titanium with octahedral geometry.
- Srivastava, Abhishek,Srivastava, Neetu,Tripathi, Umesh Nath
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- Experimental and theoretical insights into the photophysical and electrochemical properties of flavone-based hydrazones
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A small library of flavone-based hydrazones has been designed, synthesized and characterized. In this context, thirteen flavone hydrazones (3a-3 m) were synthesized by the acid-catalyzed condensation of flavone with 2,4-dinitrophenylhydrazine (2,4-DNPH) and characterized by different spectral techniques (IR, UV–Vis, NMR and mass spectrometry). The electrochemical, photophysical and theoretical investigations of such type of compounds are hitherto unknown. The electrochemical behavior of these hydrazones at a platinum electrode has been analyzed by cyclic voltammetry (CV) and was investigated at 200, 100 and 40 mVs?1 in acetonitrile (CH3CN). These hydrazones showed a quasi-reversible redox reaction. The oxidation–reduction reactive sites of these derivatives were located via geometry optimization using density functional theory (DFT) at the B3LYP/3–21 g in the Guassian-09 level of theory. Moreover, the target compounds exhibited interesting fluorescent properties. Owing to their excellent photophysical and redox results, a detailed structure-property relationship was established to assess the substituents impact and their position on the physicochemical and electronic properties. All the experimental results were in accordance with the computational studies.
- Ahmed, Ishtiaq,Ahmed, Safeer,Ahmed, Saleh A.,Alsantali, Reem I.,Alsharif, Meshari A.,Altaf, Ataf Ali,Altass, Hatem M.,Jassas, Rabab. S.,Kausar, Samia,Mughal, Ehsan Ullah,Mumtaz, Amara,Naeem, Nafeesa,Obaid, Rami J.,Sadiq, Amina,Zafar, Muhammad Naveed
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- Synthesis and kinetic study for the interconversion process of some 2'-hydroxychalcones to their corresponding flavanones
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In this work, five substituted2'-Hydroxychalconeswere prepared using Claisen - Schmidt condensation and used as a synthone for substituted flavanones via base catalyzed isomerization process. The latter process has been studied kinetically using HPLC technique in (8:2) (CH3CN:CH3OH) medium at different temperatures (298 K - 318 K). The obtained results were inconsonance with a four-step mechanism which considered the existence of phenoxide ion as the key intermediate. The reaction was achieved as a pseudo first order reaction in which the rate of the studied compounds followed the sequence 1>2>3>4>5, and the activation energy had the same sequence for these compounds. The reaction rate was affected by the electronic behavior of the different substituents at ring B since they played an important role in the stability of the intermediate that led to the final product.
- Majed, Zainab Waleed,Said, Said Abdelqader,Shareef, Omar Adil
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p. 4379 - 4386
(2020/12/09)
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- Chiral Hydroxytetraphenylene-Boron Complex Catalyzed Asymmetric Diels-Alder Cycloaddition of 2′-Hydroxychalcones
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(S)-2,15-Cl2-DHTP-boron complex catalyst for the asymmetric Diels-Alder cycloaddition of 2′-hydroxychalcones and dienes was developed and tested. The resulting cyclohexenes with three chiral centers were obtained in high yields (up to 98%) with excellent stereoselectivities (up to >20:1 endo/exo, >99% ee). This catalytic system features high efficiency, broad substrate scopes, and mild reaction conditions. In addition, a DFT study was performed to explain the stereochemical course of the asymmetric induction.
- Chai, Guo-Li,Qiao, Yan,Zhang, Ping,Guo, Rong,Wang, Juan,Chang, Junbiao
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supporting information
p. 8023 - 8027
(2020/11/02)
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- Temperature-Controlled Stereodivergent Synthesis of 2,2′-Biflavanones Promoted by Samarium Diiodide
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In this work, the first example of a radical stereodivergent reaction directed towards the stereoselective synthesis of both (R*,R*)- and (R*,S*)-2,2′-biflavanones promoted by samarium diiodide is reported. Control experiments showed that the selectivity of this reaction was exclusively controlled by the temperature. It was possible to generate a variety of 2,2′-biflavanones bearing different substitution patterns at the aromatic ring in good-to-quantitative yields, being both stereoisomers of the desired compounds obtained with total or high control of selectivity. A mechanism that explains both the generation of the corresponding 2,2′-biflavanones and the selectivity is also discussed. The structure and stereochemistry determination of each isomer was unequivocally elucidated by single-crystal X-ray diffraction experiments.
- Soto, Martín,Soengas, Raquel G.,Silva, Artur M. S.,Gotor-Fernández, Vicente,Rodríguez-Solla, Humberto
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supporting information
p. 13104 - 13108
(2019/10/21)
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- Ruthenium(II)-Catalyzed Synthesis of Spirobenzofuranones by a Decarbonylative Annulation Reaction
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The first decarbonylative insertion of an alkyne through C?H/C?C activation of six-membered compounds is reported. The Ru-catalyzed reaction of 3-hydroxy-2-phenyl-chromones with alkynes works most efficiently in the presence of the ligand PPh3 to provide spiro-indenebenzofuranones. Unlike previously reported metal-catalyzed decarbonylative annulation reactions, in the present decarbonylative annulation reaction, the annulation occurs before extrusion of carbon monoxide.
- Kaishap, Partha P.,Duarah, Gauri,Sarma, Bipul,Chetia, Dipak,Gogoi, Sanjib
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supporting information
p. 456 - 460
(2018/02/21)
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- Iodine-mediated direct synthesis of 3-iodoflavones
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Molecular iodine has been used for the regioselective, one pot, direct synthesis of 3-iodoflavones from 2′-allyloxy chalcones, 2′-hydroxy chalcones and flavones. Allyl deprotection, cyclization dehydrogenation and α-iodination of 2′-allyloxychalcones has been achieved in a single step to offer 3-iodoflavones.
- Patil, Avinash M.,Kamble, Dayanand A.,Lokhande, Pradeep D.
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p. 1299 - 1307
(2018/04/05)
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- Guanidino-graphene catalysed synthesis of flavones via Aldol-Michael-oxidation
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Guanidino-graphene has been synthesized by the reaction of bromoamine with reduced graphene oxide and characterized by FT-IR, Raman, TGA, powder XRD, TEM, SEM, and zeta potential. It is a cheap, heterogeneous and environmentally benign solid base catalyst used for cascade Aldol-Michael-oxidation in the synthesis of chalcone, flavonoids.
- Mishra, Sweta,Arora, Smriti,Nagpal, Ritika,Chauhan, Shive Murat Singh
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p. 2525 - 2530
(2017/03/09)
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- In vitro and in vivo anticancer studies of 2′-hydroxy chalcone derivatives exhibit apoptosis in colon cancer cells by hdac inhibition and cell cycle arrest
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Considering the therapeutic values of bioflavonoids in colon cancer treatment, six 2′-hydroxy chalcones (C1-C6) were synthesized, characterized and screened for in vitro cytotoxicity on human colon carcinoma (HCT116) and African green monkey kidney epithe
- Pande, Aditya Narayan,Biswas, Subhankar,Reddy, Neetinkumar D.,Jayashree,Kumar, Nitesh,Rao, C. Mallikarjuna
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p. 448 - 463
(2017/05/29)
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- 2-pyrazoline derivatives in neuropharmacology: Synthesis, adme prediction, molecular docking and in vivo biological evaluation
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A novel series of 1,3,5-trisubstituted-2-pyrazoline derivatives (PFC-1 to PFC-16) were synthesized in a three step reaction using conventional and microwave assisted green chemistry approach. The synthesized derivatives were characterized and their chemic
- Upadhyay, Savita,Tripathi, Avinash C.,Paliwal, Sarvesh,Saraf, Shailendra K.
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p. 628 - 649
(2017/06/05)
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- Design, synthesis and MAO inhibitory activity of 2-(arylmethylidene)-2,3-dihydro-1-benzofuran-3-one derivatives
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A series of 2-(arylmethylidene)-2,3-dihydro-1-benzofuran-3-one derivatives (aurones, 1–20) were synthesized and screened for their inhibitory activity against hMAO. Seventeen compounds (1–5, 7–17, 19) were found to be selective towards hMAO-B, while two w
- Badavath, Vishnu Nayak,Nath, Chandrani,Ganta, Narayana Murthy,Ucar, Gulberk,Sinha, Barij Nayan,Jayaprakash, Venkatesan
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p. 1528 - 1532
(2017/07/17)
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- Synthesis, anticancer, structural, and computational docking studies of 3-benzylchroman-4-one derivatives
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A series of 3-Benzylchroman-4-ones were synthesized and screened for anticancer activity by MTT assay. The compounds were evaluated against two cancerous cell lines BT549 (human breast carcinoma), HeLa (human cervical carcinoma), and one noncancerous cell
- Simon, Lalitha,Abdul Salam, Abdul Ajees,Madan Kumar,Shilpa,Srinivasan,Byrappa
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supporting information
p. 5284 - 5290
(2017/10/30)
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- QSAR, in silico docking and in vitro evaluation of chalcone derivatives as potential inhibitors for H1N1 virus neuraminidase
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Thirty three chalcones were synthesized and tested on viral H1N1 neuraminidase activity by using MUNANA assay [2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid] assay with DANA (2,3-didehydro-2-deoxy-N-acetylneuraminic acid) was used as standard. 2D and 3D-quantitative structure?activity relationship models have been successfully developed with a good correlative and predictive ability for quantitative structure?activity relationships of these chalcone derivatives. Result from the 2D-quantitative structure?activity relationship model indicates that electrostatic parameter enhanced bioactivity of the chalcones while steric substituents diminished their potency as H1N1 neuraminidase inhibitors. 3D-quantitative structure?activity relationship model showed the importance of the position of the hydroxyl group in chalcone derivatives which can influence on hydrophobicity, hydrogen bond donor and aromatic ring features that enhance the biological activity. Finally, docking studies showed that chalcones MC8 and MC16 with low C docker interaction energies and higher numbers of hydrogen bonding have better inhibitory activity against viral H1N1 neuraminidase.
- Yaeghoobi, Marzieh,Frimayanti, Neni,Chee, Chin Fei,Ikram, Kusaira K.,Najjar, Belal O.,Zain, Sharifuddin M.,Abdullah, Zanariah,Wahab, Habibah A.,Rahman, Noorsaadah Abd.
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p. 2133 - 2142
(2016/10/25)
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- Synthesis and antiviral activity of 2-aryl-4H-chromen-4-one derivatives against Chikungunya virus
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A series of nineteen 2-aryl-4H-chromen-4-one derivatives 2a-2s were synthesized and evaluated for their antiviral activity against Chikungunya virus (LR2006-OPY1) in Vero cell culture by CPE reduction assay. Three compounds 2a, 2b and 2g, were found to be active at concentration of (IC50) 0.44 μM, 0.45 μM and 2.02 μM, respectively. Compounds having heterocyclic ring 2a and 2b at the 2nd position of the chromenone were found to be potent inhibitor of ChikV. Cytotoxicity studies were performed using Vero cell culture, compounds 2a and 2b exhibited SI of ≥100. Molecular docking simulation has been carried out to understand the possible mechanism of action.
- Badavath, Vishnu N.,Jadav, Surender S.,Pastorino, Boris,De Lamballerie, Xavier,Sinha, Barij N.,Jayaprakash, Venkatesan
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p. 1019 - 1024
(2016/11/25)
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- Synthesis, biological evaluation and molecular modelling of 2′-hydroxychalcones as acetylcholinesterase inhibitors
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A series of 2′-hydroxy- and 2′-hydroxy-4′,6′-dimethoxychalcones was synthesised and evaluated as inhibitors of human acetylcholinesterase (AChE). The majority of the compounds were found to show some activity, with the most active compounds having IC
- Sukumaran, Sri Devi,Chee, Chin Fei,Viswanathan, Geetha,Buckle, Michael J. C.,Othman, Rozana,Rahman, Noorsaadah Abd.,Chung, Lip Yong
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- Facile one-pot synthesis of flavanones using tetramethylguanidinum-based ionic liquids as catalysts
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Several tetramethylguanidinum-based ionic liquids (TMGILs) were prepared, characterized and used as catalysts in one-pot synthesis of flavanones. The results indicated that TMGILs composed of phenolate anion was beneficial for one-pot synthesis of flavanones, and [TMG][4-MeO-PhO] induced the good yields of flavanones owing to the electron-donating effect of methoxy substituent on phenolate anion. Furthermore, [TMG][4-MeO-PhO] was found to be used repetitively at least five times without obvious decrease in activity and quantity.
- Zhou, Yan,Huang, Wei,Chen, Xiang-Shu,Song, Zhi-Bin,Tao, Duan-Jian
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p. 1830 - 1836
(2019/11/28)
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- Monoamine oxidase inhibitory activity of 2-aryl-4H-chromen-4-ones
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A series of twenty 2-aryl-4H-chromen-4-one (flavones) derivatives (3a-3s) were synthesized and tested for hMAO inhibitory activity. Fifteen compounds (3a, 3c, 3e-3h, 3j-3p, 3r, 3s) were found to be selective towards MAO-B, while 3d was selective towards MAO-A, and 3b, 3i and 3q were non-selective. Experimental Selectivity Index for MAO-B ranges from 2.0 (3g, 3p) to 30.0 (3j). Compound 3j, which is carrying 3,4-di-OMeC6H3 groups at R position on the molecule, was found to be potent MAO-B inhibitor amongst the fifteen with Ki value for MAO-B of 0.16 ± 0.01 lM comparable to that of standard drug, Selegiline (Ki for MAO-B is 0.16 ± 0.01 μM). Compound 3j also appeared as the most selective MAO-B inhibitor according to its best selectivity index (30.0), which is comparable to that of Selegiline (SIMAO-B = 35.0). Molecular docking and molecular dynamics simulation studies were carried out using Autodock-4.0 and Amber12 to understand the molecular level interaction and energy relation of MAO isoforms with selective inhibitors (3d and 3j). Simulation results are in good agreement with the experimental results. Leads identified may further be explored to develop potent isoform specific inhibitors of MAO.
- Nayak, Badavath Vishnu,Ciftci-Yabanoglu,Bhakat, Soumendranath,Timiri, Ajay Kumar,Sinha, Barij N.,Ucar,Soliman, Mahmoud E. S.,Jayaprakash, Venkatesan
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- Modified Pyridine-Substituted Coumarins: A New Class of Antimicrobial and Antitubercular Agents
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Some new biologically potent coumarin derivatives 7a-f, 8a-f, and 9a-f bearing modified pyridine moieties (indeno[1,2-b]pyridine, 4-azaphenanthrene and benzofuro [3,2-b]pyridine) at the sixth position were designed and synthesized. All the synthesized com
- Giri, Rakesh R.,Lad, Hemali B.,Bhila, Varun G.,Patel, Chirag V.,Brahmbhatt
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p. 363 - 375
(2015/10/29)
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- Absorption and fluorescent studies of 3-hydroxychromones
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The synthesis and spectral studies of variously substituted 3-hydroxychromones have been carried out. A key relationship between the structural motif of synthesized 3-hydroxychromones (3-HCs) and their fluorescent properties was found. The chromones substituted with electron-donating group at 4′-position expressed the red shift of the N and T band and also exhibited the increased fluorescent intensity ratio while the chromones with electron-withdrawing group showed the blue shift of the N and T band. Therefore, these 3-HCs may behave as the possible fluorescent probes.
- Khanna, Radhika,Kumar, Ramesh,Dalal, Aarti,Kamboj, Ramesh C.
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p. 1159 - 1163
(2015/10/20)
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- The rearrangement of tosylated flavones to 1′-(alkylamino)aurones with primary amines
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A rearrangement of 3-tosylflavone to the corresponding 1′-(alkylamino)aurone proceeds under mild conditions in the presence of primary amines in high yields. The reaction is applicable to different substituted 3-tosylflavones and alkyl amines and the respective aurones were isolated as a mixture of E/Z isomers. Further conversion of 1′-(methylamino)aurone to the corresponding thionated compound was performed by reaction with Lawesson's reagent and only the E isomer was obtained. This observation can be explained by the weaker exocyclic double bond, which facilitates rotation and the formation of the thermodynamically preferred E form. The characterization, preliminary biological investigations of the synthesized compounds and lipophilicity studies are discussed.
- Kandioller, Wolfgang,Kubanik, Mario,Bytzek, Anna K.,Jakupec, Michael A.,Roller, Alexander,Keppler, Bernhard K.,Hartinger, Christian G.
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p. 8953 - 8959
(2015/11/02)
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- Nanosilica-supported dual acidic ionic liquid as a heterogeneous and reusable catalyst for the synthesis of flavanones under solvent-free conditions
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[Figure not available: see fulltext.] A nanosilica-supported dual acidic ionic liquid on the basis of 1-methyl-3-(4-sulfobutyl)imidazolium hydrogen sulfate was synthesized and used as an efficient, green, non-corrosive, non-toxic, heterogeneous, and reusable catalyst for the synthesis of some new and known substituted flavanones. The synthesis was done by the condensation of 2'-hydroxyacetophenone with different aldehydes and the subsequent cyclization of the resulting 2'-hydroxychalcone in the presence of the catalyst. High yields of the products, short reaction times, and solvent-free conditions characterize this new method.
- Rostamizadeh, Shahnaz,Zekri, Negar,Tahershamsi, Leili
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p. 526 - 530
(2016/02/16)
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- SAR studies of o-hydroxychalcones and their cyclized analogs and study them as novel inhibitors of cathepsin B and cathepsin H
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Cathepsins have emerged as a potential target for anti-cancer drug development. In the present study, we have synthesized three structurally related series of flavanoids i.e., 2′-hydroxychalcones, flavanones and flavones and assayed in vitro to study their inhibitory potency against cathepsin B and H, promising drug candidate for cancer therapy. Enzyme kinetics studies were carried out in presence of these compounds after preliminary proteolytic studies on endogenous protein substrates. SAR studies suggested that open chain flavanoids were better inhibitors as compared to their cyclized analogs. The most potent inhibitors among the three series were nitro substituted compounds 1g, 2g and 3g with Ki values of ~6.18 × 10-8 M, 4.8 × 10-7 M and 7.85 × 10-7 M for cathepsin B and Ki values of ~2.8 × 10-7 M, 31.8 × 10-6 M and 33.7 × 10 -6 M for cathepsin H, respectively. The relationship between chalcone, flavanones and flavone structures interpreted by docking studies on cathepsin B and H also provided useful insights.
- Raghav,Garg
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- Aurones as histone deacetylase inhibitors: Identification of key features
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In this study, a total of 22 flavonoids were tested for their HDAC inhibitory activity using fluorimetric and BRET-based assays. Four aurones were found to be active in both assays and showed IC50 values below 20 μM in the enzymatic assay. Molecular modelling revealed that the presence of hydroxyl groups was responsible for good compound orientation within the isoenzyme catalytic site and zinc chelation.
- Zwick, Vincent,Chatzivasileiou, Alkiviadis-Orfefs,Deschamps, Nathalie,Roussaki, Marina,Simes-Pires, Claudia A.,Nurisso, Alessandra,Denis, Iza,Blanquart, Christophe,Martinet, Nadine,Carrupt, Pierre-Alain,Detsi, Anastasia,Cuendet, Muriel
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supporting information
p. 5497 - 5501
(2014/12/12)
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- Monoamine oxidase inhibitory activity of 2-aryl-4H-chromen-4-ones
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A series of twenty 2-aryl-4H-chromen-4-one (flavones) derivatives (3a-3s) were synthesized and tested for hMAO inhibitory activity. Fifteen compounds (3a, 3c, 3e-3h, 3j-3p, 3r, 3s) were found to be selective towards MAO-B, while 3d was selective towards MAO-A, and 3b, 3i and 3q were non-selective. Experimental Selectivity Index for MAO-B ranges from 2.0 (3g, 3p) to 30.0 (3j). Compound 3j, which is carrying 3,4-di-OMeC6H3 groups at R position on the molecule, was found to be potent MAO-B inhibitor amongst the fifteen with Ki value for MAO-B of 0.16 ± 0.01 μM comparable to that of standard drug, Selegiline (Ki for MAO-B is 0.16 ± 0.01 μM). Compound 3j also appeared as the most selective MAO-B inhibitor according to its best selectivity index (30.0), which is comparable to that of Selegiline (SIMAO-B = 35.0). Molecular docking and molecular dynamics simulation studies were carried out using Autodock-4.0 and Amber12 to understand the molecular level interaction and energy relation of MAO isoforms with selective inhibitors (3d and 3j). Simulation results are in good agreement with the experimental results. Leads identified may further be explored to develop potent isoform specific inhibitors of MAO.
- Badavath, Vishnu Nayak,Ciftci-Yabanoglu,Bhakat, Soumendranath,Timiri, Ajay Kumar,Sinha, Barij N.,Ucar,Soliman, Mahmoud E.S.,Jayaprakash, Venkatesan
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- Cyclization of 2'-hydroxychalcones to flavones using ammonium iodide as an iodine source - An eco-friendly approach
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Ammonium iodide on exposure to air decomposes to ammonia and iodine. The in situ generated iodine was used for the cyclization of 2'-hydroxychalcones to the corresponding flavones under solvent-free conditions in good to excellent yields. This method could serve as an attractive alternative to the existing methods for synthesis of flavones and the use of toxic molecular iodine is avoided. Copyright
- Kulkarni, Pramod S.,Kondhare, Dasharath D.,Varala, Ravi,Zubaidha, Pudukulathan K.
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p. 909 - 916
(2013/08/23)
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- Rhodium(Cp*) compounds with flavone-derived ligand systems: Synthesis and characterization
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Organometallic rhodium complexes have been reported to exhibit promising anticancer activity and some examples have been investigated more extensively over the last years. Based on recent successes of cytotoxic rhodium compounds, this work describes the synthesis and characterization of organorhodium(III) complexes with 3-hydroxyflavones as bidentate ligands and η5- coordinated pentamethylcyclopentadienyl (Cp*). The organorhodium compounds were synthesized and characterized by means of NMR spectroscopy and single crystals of the compounds were characterized by X-ray diffraction analysis. Interestingly, the rhodium complexes were isolated with methanol or triflate coordinated to the central rhodium atom, yielding positively-charged and neutral complexes, respectively. However, none of the complexes prepared were sufficiently soluble in aqueous media to allow testing their cytotoxicity. Copyright
- Schwarz, Martina B.,Kurzwernhart, Andrea,Roller, Alexander,Kandioller, Wolfgang,Keppler, Bernhard K.,Hartinger, Christian G.
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p. 1648 - 1654
(2013/08/23)
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- Monoamine oxidase inhibitory activity of 3,5-biaryl-4,5-dihydro-1H- pyrazole-1-carboxylate derivatives
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Ethyl and phenyl carbamate derivatives of pyrazoline (3a-3h) were synthesized and tested for their MAO inhibitory activity. All the compounds were found to be selective towards MAO-A. Phenyl carbamates (3e-3h) were better than ethyl carbamates (3a-3d) and
- Vishnu Nayak,Ciftci-Yabanoglu,Jadav, Surender Singh,Jagrat, Monika,Sinha, Barij N.,Ucar,Jayaprakash, Venkatesan
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p. 762 - 767
(2013/10/22)
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- Asymmetric ion-pairing catalysis of the reversible cyclization of 2'-hydroxychalcone to flavanone: Asymmetric catalysis of an equilibrating reaction
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The asymmetric catalytic cyclization of the simple 2'-hydroxychalcone (1) to flavanone (2), a model for the chalcone isomerase reaction, has been realized as a catalytic asymmetric ion-pairing process with chiral quaternary ammonium salts (e.g., 9-anthracenylmethlycinchoninium chloride; 9-Am-CN-Cl) and NaH as small-molecule co-catalyst. In toluene/CHCl3 solution, the process reaches an intrinsic enantioselectivity of up to S = 14.4 (er = 93.5:6.5). The reversible reaction proceeds in two steps: A fast initial reaction approaches a quasi-equilibrium with KR/S = 4.5, followed by a second, slow racemization phase approaching Krac = 9. A simple mechanistic model featuring a living ion-pairing catalysis with full reversibility is proposed. Deuterium transfer from co-solvent CDCl3 to product 2 and isolation of a Michael conjugate formed from 2 and 1 demonstrate the intermediacy of flavanone enolate ion pairs. A kinetic model shows good agreement with the experimentally observed, peculiar, time-dependent evolution of the species concentrations and the enantiomeric excess of 2. The reaction is a chemical model of the chalcone isomerase enzymatic reaction. Furthermore, it is an ideal model for studying the characteristic behavior of reversible asymmetric catalyses close to their equilibria.
- Hintermann, Lukas,Dittmer, Claudia
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supporting information
p. 5573 - 5584
(2012/11/13)
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- Targeting the DNA-topoisomerase complex in a double-strike approach with a topoisomerase inhibiting moiety and covalent DNA binder
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RuII(arene)-flavonoids with high in vitro antitumour activity were synthesised. These compounds are capable of inhibiting human topoisomerase IIα and binding covalently to DNA.
- Kurzwernhart, Andrea,Kandioller, Wolfgang,Bartel, Caroline,Baechler, Simone,Trondl, Robert,Muehlgassner, Gerhard,Jakupec, Michael A.,Arion, Vladimir B.,Marko, Doris,Keppler, Bernhard K.,Hartinger, Christian G.
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supporting information; experimental part
p. 4839 - 4841
(2012/06/30)
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- In silico studies on 2,3-dihydro-1,5-benzothiazepines as cholinesterase inhibitors
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In vitro studies on cholinesterase inhibitory potential on the three sets of 2,3-dihydro-1,5-benzothiazepines have been carried out. The compounds in Set 1 were unsubstituted on ring A, while those in Sets 2 and 3 had a 2′- and 3′-hydoxy substituent, respectively, in ring A. These studies revealed that they are mixed inhibitors of both AChE and BChE as reflected from their IC50 values. It was further observed that 3′-hydroxy substituted benzothiazepines (Set 3) were found to have stronger affinity for both AChE and BChE compared with those of Sets 1 and 2. Moreover, all the compounds in Set 3 were found to be stronger BChE inhibitors than AChE. These experimental observations were rationalized by conducting in silico studies using molecular docking tool of Molecular Operating Environment (MOE) software, thereby, a good correlation was observed between IC50 values and their binding interactions within the enzyme active site. We have observed that these interactions were electrostatic and hydrophobic in nature besides hydrogen bonding. The high BChE inhibitory potential of 3′-hydroxy substituted benzothiazepines was found to be cumulative effect of hydrogen bonding and π-π interactions between the ligand and BChE. These findings may serve as a guideline for synthesizing more potent ChE inhibitors for the treatment of Alzheimer's disease and related dementias. Springer Science+Business Media, LLC 2011.
- Ansari, Farzana Latif,Kalsoom, Saima,Zaheer-Ul-Haq,Ali, Zahra,Jabeen, Farukh
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p. 2329 - 2339
(2012/11/07)
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- An unexpected rearrangement-hydration reaction sequence of 2H-chromenes to dihydrochalcones under catalysis of HAuCl4
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2-Aryl-2H-chromenes in aqueous DCM medium under catalysis of HAuCl 4 are converted into 3-(2-hydroxyaryl)-1-arylpropan-1-ones through hydration-rearrangement reaction sequence in very good yield. The key step probably involves the [1,5] hydride shift followed by the hydrolysis under the reaction condition. The notable advantages of this method are operational simplicity and ease of isolation of products and also provide a pathway to convert the chalcone into DHCs with the transposition of carbonyl group. 2012 Elsevier Ltd. All rights reserved.
- Maiti, Gourhari,Kayal, Utpal,Karmakar, Rajiv,Bhattacharya, Rudraksha N.
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p. 6321 - 6325,5
(2012/12/12)
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- Structure-Activity relationships of targeted RuII(η 6- P -Cymene) anticancer complexes with flavonol-Derived ligands
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RuII(arene) complexes have been shown to be promising anticancer agents, capable of overcoming major drawbacks of currently used chemotherapeutics. We have synthesized RuII(η6-arene) compounds carrying bioactive flavonol ligands with the aim to obtain multitargeted anticancer agents. To validate this concept, studies on the mode of action of the complexes were conducted which indicated that they form covalent bonds to DNA, have only minor impact on the cell cycle, but inhibit CDK2 and topoisomerase IIα in vitro. The cytotoxic activity was determined in human cancer cell lines, resulting in very low IC50 values as compared to other RuII(arene) complexes and showing a structure-activity relationship dependent on the substitution pattern of the flavonol ligand. Furthermore, the inhibition of cell growth correlates well with the topoisomerase inhibitory activity. Compared to the flavonol ligands, the RuII(η6-p-cymene) complexes are more potent antiproliferative agents, which can be explained by potential multitargeted properties.
- Kurzwernhart, Andrea,Kandioller, Wolfgang,B?chler, Simone,Bartel, Caroline,Martic, Sanela,Buczkowska, Magdalena,Mühlgassner, Gerhard,Jakupec, Michael A.,Kraatz, Heinz-Bernhard,Bednarski, Patrick J.,Arion, Vladimir B.,Marko, Doris,Keppler, Bernhard K.,Hartinger, Christian G.
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p. 10512 - 10522
(2013/02/22)
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- Synthesis of flavanones by use of anhydrous potassium carbonate as an inexpensive, safe, and efficient basic catalyst
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Anhydrous potassium carbonate has been utilized as an inexpensive, safe, and efficient basic catalyst for the synthesis of flavanones starting either from 2′-hydroxychalcones or from 2′-hydroxyacetophenones. In both the cases the favored reaction condition was either refluxing in a solvent with added catalyst or microwave irradiation on the catalyst.
- Mondal, Rina,Gupta, Arpita Das,Mallik, Asok K.
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experimental part
p. 5020 - 5024
(2011/10/19)
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- Lanthanum nitrate-catalyzed synthesis of new 2,3-dihydro-1,5- benzothiazepines
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Simple and convenient procedure have been developed for the synthesis of optically active1,5-benzothiazepine derivatives by reaction of 2-aminothiophenol with newly synthesized Chalcones under mild conditions in the presence of catalytic amount of Lanthan
- Khan, Asgar Jafar,Baseer, Mohammad A.
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body text
p. 1759 - 1762
(2012/06/15)
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- A new series of flavones, thioflavones, and flavanones as selective monoamine oxidase-B inhibitors
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A new series of synthetic flavones, thioflavones, and flavanones has been synthesized and evaluated as potential inhibitors of monoamine oxidase isoforms (MAO-A and -B). The most active series is the flavanone one with higher selective inhibitory activity against MAO-B. Some of these flavanones (mainly the most effective) have been separated and tested as single enantiomers. In order to investigate the MAOs recognition of the most active and selective compounds, a molecular modeling study has been performed using available Protein Data Bank (PDB) structures as receptor models for docking experiments.
- Chimenti, Franco,Fioravanti, Rossella,Bolasco, Adriana,Chimenti, Paola,Secci, Daniela,Rossi, Francesca,Yá?ez, Matilde,Orallo, Francisco,Ortuso, Francesco,Alcaro, Stefano,Cirilli, Roberto,Ferretti, Rosella,Sanna, M. Luisa
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experimental part
p. 1273 - 1279
(2010/04/24)
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- Studies on ruthenium(III) chalcone thiosemicarbazone complexes as catalysts for carbon-carbon coupling
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New six-coordinate ruthenium(III) complexes [RuX(EPh3)2(L)] (X = Cl or Br; E = P or As; L = chalcone thiosemicarbazone) have been prepared by reacting [RuX3(EPh3)3] (X = Cl or Br; E = P or As) with chalcone thiosemicarbazones in benzene under reflux. The new complexes have been characterized by analytical and spectroscopic (IR, electronic, mass, and EPR) data. The redox behavior of the complexes has also been studied. Based on the above data, an octahedral structure has been assigned for all the complexes. The new complexes exhibit catalytic activity for carbon-carbon coupling reactions.
- Muthukumar,Sivakumar,Viswanathamurthi,Karvembu,Prabhakaran,Natarajan
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experimental part
p. 296 - 306
(2010/09/10)
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- Synthesis and cytotoxic activity of 4-aryl-4H-chromeno[4,3-d] [1,2,3] selenadiazoles
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Fourteen 4-Aryl-4H-chromeno[4,3-d][1,2,3] selenadiazole derivatives were synthesized by the reaction of fla-vonone-4-semicarbazones with SeO2. The structures of the target compounds 1a-n were elucidated by 1H NMR, IR spectra, ESI-MS and elemental analyses. The preliminary cytotoxic activities of 1a-n against K562, KB, A549, SMC-7721 and SGC-7901 cell lines were evaluated by MTT method, indicating that most compounds displayed moderate to good antiproliferative activities against K562 and KB cell lines. Compounds 1m and 1n, the most potent ones, were promising template for development of novel potent antitumor agents.
- Yin, Hong,Huang, Yueyan,Song, Guojie
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p. 721 - 725
(2013/01/09)
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- Discovery and optimization of chromenotriazolopyrimidines as potent inhibitors of the mouse double minute 2-tumor protein 53 protein-protein interaction
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Tumor protein 53 (p53) is a critical regulator of cell cycle and apoptosis that is frequently disabled in human tumors. In many tumor types, p53 is deleted or mutated, but in others p53 is inactivated by overexpression or amplification of its negative reg
- Allen, John G.,Bourbeau, Matthew P.,Wohlhieter, G. Erich,Bartberger, Michael D.,Michelsen, Klaus,Hungate, Randall,Gadwood, Robert C.,Gaston, Rick D.,Evans, Bruce,Mann, Larry W.,Matison, Michael E.,Schneider, Stephen,Huang, Xin,Yu, Dongyin,Andrews, Paul S.,Reichelt, Andreas,Long, Alexander M.,Yakowec, Peter,Yang, Evelyn Y.,Lee, Tani Ann,Oliner, Jonathan D.
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experimental part
p. 7044 - 7053
(2010/08/05)
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- Synthesis of 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-dione derivatives
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A preparative procedure for the synthesis of 2-alkyl-1-aryl-1,2- dihydrochromeno[2,3-c]pyrrole-3,9-diones from methyl 4-(o-hydroxyphenyl)-2,4- dioxobutanoate, aromatic aldehyde, and aliphatic amine is described.
- Vydzhak,Panchishin, S. Ya.
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experimental part
p. 2391 - 2397
(2009/05/30)
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- Enantioselective synthesis of chromanes by iridium-catalyzed asymmetric hydrogenation of 4H-chromenes
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Iridium complexes of chiral oxazoline-based P,N-ligands proved to be efficient catalysts for the enantioselective hydrogenation of 2-aryl- and 2-alkyl-4H-chromenes. The best results were obtained with a ligand derived from threonine (ThrePHOX), which induced ee values of 95% to >99% in the hydrogenation of 2-methyl-, 2-cyclohexyl- and various 2-aryl-substituted chromenes. Georg Thieme Verlag Stuttgart.
- Valla, Carine,Baeza, Alejandro,Menges, Frederik,Pfaltz, Andreas
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scheme or table
p. 3167 - 3171
(2009/06/17)
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- Synthesis of flavanones using nanocrystalline MgO
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The design and development of a truly nano heterogeneous catalyst for the Claisen-Schmidt condensation (CSC) of benzaldehydes with 2-hydroxyacetophenone to yield substituted chalcones followed by isomerization to afford flavanones with excellent yields and selectivity is described.
- Choudary,Ranganath,Yadav, Jagajit,Lakshmi Kantam
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p. 1369 - 1371
(2007/10/03)
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- New synthesis of flavanones catalyzed by L-proline
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L-Proline is utilized as an efficient organocatalyst for the synthesis of substituted flavanones and chalcones in good yields. The efficiency of the catalyst was proved with a variety of substrates ranging from electron-deficient to electron-rich aryl aldehydes and 2-hydroxyacetophenones.
- Chandrasekhar,Vijeender,Venkatram Reddy
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p. 6991 - 6993
(2007/10/03)
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- CHALCONE OXIMES. PART V. REACTION OF HYDROXYLAMINE WITH 4-SUBSTITUTED 2'-HYDROXYCHALCONES
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The reactions of hydroxylamine with 4-substituted 2'-hydroxychalcones have been investigated.Formation of products of 1,2 addition and simultaneous 1,4 and 1,2 addition for R = -CH3, -Cl have been established.Products of 1,2 addition for R = -OCH3 and of
- Witczak, Zbigniew,Krolikowska, Maria
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