Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones

Hydroxylated coumarins and chalcones are known to possess potent antioxidant activities. The present study highlights the synthesis of two hydroxycoumarins namely 3-acetyl-7-hydroxycoumarin and 3-acetyl-6- hydroxycoumarin. Both compounds were synthesized using the Knoevenagel condensation method wit...

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Main Author:	Suleiman, Mohamad Shafiq
Format:	Thesis
Language:	English
Published:	2016
Subjects:	QD Chemistry
Online Access:	http://eprints.utm.my/id/eprint/78203/1/MohamadShafiqSuleimanMFS2016.pdf
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spelling	my-utm-ep.782032018-07-28T06:28:48Z Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones 2016-02 Suleiman, Mohamad Shafiq QD Chemistry Hydroxylated coumarins and chalcones are known to possess potent antioxidant activities. The present study highlights the synthesis of two hydroxycoumarins namely 3-acetyl-7-hydroxycoumarin and 3-acetyl-6- hydroxycoumarin. Both compounds were synthesized using the Knoevenagel condensation method with respective hydroxybenzaldehydes under basic conditions. The synthesized hydroxycoumarins served as an intermediate for the subsequent coupling reaction to produce three new coumarinyl chalcones known as 7-hydroxy-3- [3-(4'-hydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one, 6-hydroxy-3-[3-(4'- hydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one and 7-hydroxy-3-[3-(3',4'- dihydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one respectively. The target products were synthesized via the Claisen-Schmidt condensation reaction utilizing the Lewis acid, boron trifluoride-etherate (BF3-Et2O) in 1,4-dioxane. The structures of the synthetic compounds were confirmed by spectroscopic techniques which includes the Infrared (IR) and Nuclear Magnetic Resonance (NMR) (1H, 13C and DEPT) Spectroscopies. The antioxidant activities of all synthesized compounds were evaluated using three antioxidant assays known as the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and Ferric Reducing Ability of Plasma (FRAP) assays using the Bio-Tek Epoch microplate reader. Among the compounds tested, the coumarinyl chalcones exhibited a better antioxidant activity compared to the hydroxycoumarins. 7-Hydroxy-3-[3-(3',4'- dihydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one proved to be the best antioxidant in all assays with SC50 values of 0.57 mM and 0.036 mM in the ABTS and DPPH assays respectively. The FRAP value of this compound falls between the range of 0.09 mM to 1.67 mM. The values were comparable with the positive control used in these assays known as butylated hydroxyanisole (BHA). 2016-02 Thesis http://eprints.utm.my/id/eprint/78203/ http://eprints.utm.my/id/eprint/78203/1/MohamadShafiqSuleimanMFS2016.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:95316 masters Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	QD Chemistry
spellingShingle	QD Chemistry Suleiman, Mohamad Shafiq Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones
description	Hydroxylated coumarins and chalcones are known to possess potent antioxidant activities. The present study highlights the synthesis of two hydroxycoumarins namely 3-acetyl-7-hydroxycoumarin and 3-acetyl-6- hydroxycoumarin. Both compounds were synthesized using the Knoevenagel condensation method with respective hydroxybenzaldehydes under basic conditions. The synthesized hydroxycoumarins served as an intermediate for the subsequent coupling reaction to produce three new coumarinyl chalcones known as 7-hydroxy-3- [3-(4'-hydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one, 6-hydroxy-3-[3-(4'- hydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one and 7-hydroxy-3-[3-(3',4'- dihydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one respectively. The target products were synthesized via the Claisen-Schmidt condensation reaction utilizing the Lewis acid, boron trifluoride-etherate (BF3-Et2O) in 1,4-dioxane. The structures of the synthetic compounds were confirmed by spectroscopic techniques which includes the Infrared (IR) and Nuclear Magnetic Resonance (NMR) (1H, 13C and DEPT) Spectroscopies. The antioxidant activities of all synthesized compounds were evaluated using three antioxidant assays known as the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and Ferric Reducing Ability of Plasma (FRAP) assays using the Bio-Tek Epoch microplate reader. Among the compounds tested, the coumarinyl chalcones exhibited a better antioxidant activity compared to the hydroxycoumarins. 7-Hydroxy-3-[3-(3',4'- dihydroxyphenyl)prop-2-enoyl]-2H-1-benzopyran-2-one proved to be the best antioxidant in all assays with SC50 values of 0.57 mM and 0.036 mM in the ABTS and DPPH assays respectively. The FRAP value of this compound falls between the range of 0.09 mM to 1.67 mM. The values were comparable with the positive control used in these assays known as butylated hydroxyanisole (BHA).
format	Thesis
qualification_level	Master's degree
author	Suleiman, Mohamad Shafiq
author_facet	Suleiman, Mohamad Shafiq
author_sort	Suleiman, Mohamad Shafiq
title	Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones
title_short	Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones
title_full	Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones
title_fullStr	Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones
title_full_unstemmed	Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones
title_sort	synthesis and antioxidant activities of hydroxylated coumarinyl chalcones
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2016
url	http://eprints.utm.my/id/eprint/78203/1/MohamadShafiqSuleimanMFS2016.pdf
_version_	1747817932275056640

Synthesis and antioxidant activities of hydroxylated coumarinyl chalcones

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