2875-23-2Relevant academic research and scientific papers
Solvent influence on excited-state intramolecular proton transfer in 3-hydroxychromone derivatives studied by cryogenic high-resolution fluorescence spectroscopy
Bader, Arjen N.,Pivovarenko, Vasyl,Demchenko, Alexander P.,Ariese, Freek,Gooijer, Cees
, p. 1593 - 1603 (2003)
High-resolution Shpol'skii spectra (recorded at 10 K in n-octane) of 3-hydroxychromone (3HC) substituted at the 2-position with a furan (3HC-F), a benzofuran (3HC-BF) or a naphthofuran group (3HC-NF) are presented. Being close analogues of 3-hydroxyflavone (3HF), these compounds can undergo excited-state intramolecular proton transfer (ESIPT). Luminescence can occur from the normal N* state (blue) or from the tautomeric T* state (green). Whether blue or green emission is observed is strongly dependent on hydrogen-bonding interactions with the environment. For all three chromones studied, high-resolution emission spectra in the green region (T*→T) were obtained in pure n-octane, showing four sites with distinct emission bands and detailed vibrational structures, whereas no blue emission was detected. Contrary to the spectra published for 3HF, the emission lines were very narrow (line-broadening effects beyond detection) which implies that the ESIPT rate constants are >1012 s-1, at least 25 times lower than for 3HF. In order to study the effects of hydrogen-bonding solvents, four isomers of octanol (1-, 2-, 3- and 4-octanol) were added, forming 1:1 complexes with the 3HC derivatives. For all the combinations considered both blue and additional green emission was observed and in some cases narrow-banded spectra were obtained, mostly in the green. Only for the 3HC-NF/2-octanol complex, narrow-banded emission was found both in the blue and in the green region. It is demonstrated that these emissions come from different configurations of the complex. Possible structures for the two complex species are proposed, supported by semi-empirical calculations on complex formation enthalpies.
Thallium(III) p-tosylate-mediated oxidative [1,2] rearrangement of 2-naphthyl and 2-heteroarylchromanones
Kurapati, Chidvilas,Muthukrishnan, Murugan,Singh, Om V.,Gundla, Rambabu
supporting information, p. 172 - 177 (2021/10/29)
A practical and effective approach towards the synthesis of 3-heteroaryl-4H-chromen-4-ones by the oxidative [1,2] rearrangement of the respective 2-heteroaryl chroman-4-ones using thallium(III) p-tosylate is presented. The oxidative rearrangement of α- an
Water stable fluorescent organotin(iv) compounds: aggregation induced emission enhancement and recognition of lead ions in an aqueous system
Capalash, Neena,Kaur, Kulwinder,Kaur, Varinder,Singh, Raghubir
, p. 148 - 161 (2021/12/31)
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.
A novel one-pot synthesis of flavones
Chang, Meng-Yang,Tsai, Min-Chen,Lin, Chun-Yi
, p. 11655 - 11662 (2021/03/31)
In this paper, a one-pot facile route for the BiCl3/RuCl3-mediated synthesis of functionalized flavones is described, including: (i) intermolecularortho-acylation of substituted phenols with cinnamoyl chlorides, and (ii) intramolecular cyclodehydrogenation of the resultingo-hydroxychalcones. The reaction conditions are discussed herein.
Exploring 3-hydroxyflavone scaffolds as mushroom tyrosinase inhibitors: synthesis, X-ray crystallography, antimicrobial, fluorescence behaviour, structure-activity relationship and molecular modelling studies
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
, p. 7107 - 7122 (2020/08/21)
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.
Glycolytic inhibition and antidiabetic activity on synthesized flavanone scaffolds with computer aided drug designing tools
Kiruthiga, Natarajan,Saravanan, Govindaraj,Selvinthanuja, Chellappa,Sivakumar, Thangavel,Srinivasan, Kulandaivel
, p. 574 - 592 (2021/09/30)
Background: Diabetes mellitus is a challengeable metabolic disorder that leads to a group of complications when the HbA1c level is not maintained. Most of the existing drugs avail-able in the market in long-term use may lead to serious adverse effects. He
Convenient synthesis of flavanone derivatives via oxa-Michael addition using catalytic amount of aqueous cesium fluoride
Miura, Motofumi,Shigematsu, Karin,Toriyama, Masaharu,Motohashi, Shigeyasu
supporting information, (2021/10/25)
A total of 36 flavanones, which included polycyclic aromatic and heterocyclic rings, were readily synthesized via oxa-Michael addition from the corresponding hydroxychalcones with a catalytic amount of aqueous cesium fluoride solution under mild conditions. This method could be applied to the scalable synthesis of eriodictyol as a known potent inhibitor of the SARS-CoV-2 spike protein.
Synthetic Aurones: New Features for Schistosoma mansoni Therapy
Alves da Silva Filho, Ademar,Alves de Oliveira, Bruna,Azevedo Alves, Lara,Fortini Grenfell e Queiroz, Rafaella,Gomes Vasconcelos, Eveline,Paulo da Silva, Marcos,Silva Torres, Daniel,Vanessa Zabala Capriles Goliatt, Priscila,de Faria Pinto, Priscila,Carius de Souza, Vinícius,Martins Parreiras, Patrícia,Moraes, Josué,Rúbia Costa Couri, Mara,Roberto Silva, Márcio,Rodrigues Dur?es Pereira, Vinícius,Souza d Silveira, Lígia
, (2021/10/23)
In this work, two synthetic aurones revealed moderate schistosomicidal potential in in vitro and in vivo assays. Aurones (1) and (2) promoted changes in tegument integrity and motor activity, leading to death of adult Schistosoma mansoni worms in in vitro
Spectroscopic analysis by NMR, FT-Raman, ATR-FTIR, and UV-Vis, evaluation of antimicrobial activity, and in silico studies of chalcones derived from 2-hydroxyacetophenone
Xavier, Jayze da Cunha,de Almeida-Neto, Francisco W.Q.,Rocha, Janaína E.,Freitas, Thiago S.,Freitas, Priscila R.,de Araújo, Ana C.J.,da Silva, Priscila T.,Nogueira, Carlos E.S.,Bandeira, Paulo N.,Marinho, Márcia M.,Marinho, Emmanuel S.,Kumar, Nitin,Barreto, Ant?nio C.H.,Coutinho, Henrique D.M.,Juli?o, Murilo S.S.,dos Santos, Hélcio S.,Teixeira, Alexandre M.R.
, (2021/05/31)
Six 2’-hydroxychalcones were synthesized and characterized by NMR, FT-Raman, ATR-FTIR, and UV-Vis. These chalcones alone and in combination with the ciprofloxacin, penicillin, and erythromycin antibiotics were tested against multiresistant strains of Staphylococcus aureus. It was also verified by in vitro and in silico studeis the capacity of these chalcones to inhibit the NorA efflux pump. The MICs values of ciprofloxacin were reduced in the presence of all tested chalcones. For norfloxacin antibiotic, the chalcones A1, A4, A5 and A6 promoted the reduced in the MIC values. The A2 chalcone was the only one to reduce the MIC values when associated with penicillin. Any chalcones were not able to reduce MIC values when associated with erythromycin. These results indicate that the synergistic effects demonstrated for the synthesized chalcones were influenced by the introduction of a furanic ring (A1), a chlorine atom and a methoxy group at the C4 position (A2 and A4), a second double bond (A5), and a fluorine atom at the C2 position (A6). The ADMET analysis predicts that the chalcones A2, A3, A5 and A6 have easier cell permeation. The nucleophilic region makes the A5 chalcone capable of covalently bonding with plasma proteins, and the presence of oxygenated aromatic substitutions makes the chalcones A1 and A4 more water-soluble and consequently easier to excrete. On the other hand, the substitution of the methoxy group of the A4 chalcone makes it more susceptible to O-demethylation reactions by the CYP3A4 isoenzyme. The molecular docking revealed that all six chalcones could hinder the binding of norfloxacin to the NorA efflux pump.
Biocatalytic green alternative to existing hazardous reaction media: Synthesis of chalcone and flavone derivatives via the Claisen-Schmidt reaction at room temperature
Tamuli, Kashyap J.,Sahoo, Ranjan K.,Bordoloi, Manobjyoti
supporting information, p. 20956 - 20965 (2020/12/31)
Owing to the increasing amount of waste materials around the globe, the conversion of waste or secondary by-products to value-added products for various applications has gained significant interest. Herein, two novel agro-food waste products, Musa sp. 'Malbhog' peel ash (MMPA) and Musa Champa Hort. ex Hook. F. peel ash (MCPA) are used as catalysts to promote an inexpensive, efficient and eco-friendly carbon-carbon bond forming crossed aldol reaction at room temperature in solvent free conditions. Furthermore, the resulting products were subjected to reactions with these promoters in an oxygen atmosphere and led to the formation of novel flavone derivatives. Moreover, the used catalysts were properly characterized using different sophisticated analytical techniques such as Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), Brunauer-Emmett-Teller analysis (BET), Raman spectroscopy, scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS), transition electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) along with element detection using atomic absorption spectroscopy and ion chromatographic methods. These two approaches are metal free, as well as being devoid of any extra additives, co-catalysts, harsh conditions, the use of column chromatography for purification and result in a higher yield of the product within a short space of time. The catalytic abilities of the promoter were also examined to synthesize important bioactive molecules such as butein and apigenin at room temperature. With gram scale synthesis of the chalcone derivatives, the used catalysts (MMPA and MCPA) were further reused for five cycles and did not demonstrate any loss in catalytic activity.
