Polyphenols Deriving from Chalcones: Investigations of Redox Activities (original) (raw)
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Green Synthesis and Characterization of Some Substituted Dihydroxychalcones
2015
The present communication, reports a series of novel chalcones synthesized from 2,4-dihydroxy / 2,5-dihydroxy acetophenone with substituted benzaldehydes by Claisen-Schimidt base catalyzed condensation and characterized by T.L.C. studies, elemental analysis, conductivity measurements, I.R. spectral studies. The aim of this study is to procure various dihydroxychalcone derivatives in the hope of obtaining new agents, which might show biological activities with improved potency.
Green Synthesis and Characterization of Some Substituted Dihydroxychalcones Dr
2015
The present communication, reports a series of novel chalcones synthesized from 2,4-dihydroxy / 2,5-dihydroxy acetophenone with substituted benzaldehydes by Claisen-Schimidt base catalyzed condensation and characterized by T.L.C. studies, elemental analysis, conductivity measurements, I.R. spectral studies. The aim of this study is to procure various dihydroxychalcone derivatives in the hope of obtaining new agents, which might show biological activities with improved potency.
Applied Sciences (ISSN 2076-3417; CODEN: ASPCC7), 2020
Background: Chalcones are part of a family of small phenolic compounds that are being extensively studied for presenting a diversity of molecular structures and biological activities. In this paper, two chalcones, (E)-1-(2-hydroxy-3,4,6-trimethoxyphenyl)-3-(3-nitrophenyl)prop-2-en-1-one (1), (E)-1-(2-hydroxy-3,4,6-trimethoxyphenyl)-3-(4-nitrophenyl)prop-2-en-1-one (2), were synthesized by Claisen-Schmidt condensation. Methods: The molecular structures of these chalcones were determined by Nuclear Magnetic Resonance and characterized by infrared, Raman spectroscopy, and electrochemical analysis at room temperature. Vibrational wavenumbers were predicted using Functional Density Theory (DFT) calculations, and their normal modes were analyzed in terms of potential energy distribution (PED). Besides this, DFT calculations were performed to obtain the molecular orbitals and their quantum descriptors. The UV-Vis absorption spectrum of the synthesized chalcones was measured and compared wi...
Synthesis and characterization of Novel (E)-1-(3, 5-bis (Benzyloxy) phenyl) -3-aryl Prop-2-en-1-ones
2014
Accepted on 20 November 2014 _____________________________________________________________________________ ABSTRACT A series of new chalcones i.e. (E)-1-(3, 5-bis (benzyloxy) phenyl)-3-aryl prop-2-en-1-ones (3a-o) have been synthesized by reacting 3, 5di benzyloxy acetophenone (1) with different substituted aromatic aldehydes (2a-o) by Claisen–Schmidt condensation. All products were obtained in good yields. The structure of the compounds have been determined by elemental analysis, FT-IR, H-NMR, C-NMR and mass spectral data.
Kinetics and Catalysis, 2010
Six antioxidants from the class of chalcones (ArOH), compounds from which flavonoids are obtained in nature, were studied. The antiradical activity of chalcones and a number of related compounds was determined by a chemiluminescence method using the scavenging of peroxide radicals ROO • + ArOH → ROOH + OAr • (with the rate constant k 7 ) in a model reaction of diphenylmethane (RH) oxidation. The structures and energies of the reagents and intermediates were determined by semiempirical quantum chem ical (PM3, PM6) calculations. 3,4 Dihydroxychalcone and caffeic acid, which have a catechol structure, that is, two neighboring OH groups in phenyl ring B, exhibited high antioxidant activity (k 7 ≈ 10 7 l mol -1 s -1 ); this is consistent with the lowest bond strengths D(ArO-H) of 79.2 and 76.6 kcal/mol, respectively. The abstrac tion of a hydrogen atom by the ROO • radical is the main reaction path of these compounds; however, the low stoichiometric coefficients of inhibition (f = 0.3-0.7) suggest a contribution of secondary and/or side reac tions of ArOH and OAr • . In the other chalcones, the ArO-H bond is stronger (D(ArO-H) = 83-88 kcal/mol) and the antioxidant activity is lower (k 7 = 10 4 -10 5 l mol -1 s -1 ).
Journal of the Serbian Chemical Society, 2011
Sixteen hydroxychalcones were synthesized in sufficient purity by the Claisen-Schmidt condensation between appropriate acetophenones and aromatic aldehydes. All the compounds were evaluated for their ability to scavenge the stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Important structure-activity relationships were observed that strongly contribute to the knowledge for the design of DPPH radical scavenging chalcones. Relevant theoretical parameters were computed in an attempt to understand and explain the obtained experimental results.
Synthesis and screening for biological potential of some substituted chalcones
IP Innovative Publication Pvt. Ltd., 2018
The present paper describes the synthesis and antibacterial as well as antioxidant activity of new chalcone derivatives derived from p-chloroacetopheneone. In the present work the reaction of p-chloroacetophenone with different substituted aromatic aldehyde. The newly synthesized chalcones (A-D) were analysed by their spectral data TLC, IR, UV and melting point. These newly synthesized compounds were evaluated for in-vitro antioxidant activity by Diphenyl Picryl Hydrazine (DPPH) model using ascorbic acid as standard and for antimicrobial activity by Cup Plate method on gram positive and gram negative bacterial strain using amoxicillin as standard. Keywords: Chalcone, Antimicrobial, Antioxidant, P-chloroacetophenone, Aromatic aldehyde.