Synthesis, X-Ray Structure Characterization And Antioxidant Activities Of Some Chalcone Derivatives Containing 2-Chlorothiophene Moiety
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Date
2021-03
Authors
Ng, Weng Zhun
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Publisher
Universiti Sains Malaysia
Abstract
A total of twelve heterocyclic chalcone compounds (1a-1l) containing 2-chlorothiophene moieties were synthesized using Claisen Schmidt Condensation process and were crystallized by slow evaporation methods. The postulate structure of these heterocyclic chalcone compounds were elucidated by FT-IR and NMR spectral analyses, followed by single crystal X-ray diffraction technique. Besides, the antioxidant potential of all compounds was evaluated using four different types of antioxidant assay which include 2, 2-diphenyl-1-picrylhydrazyl (DPPH), ferrous ion chelating (FIC), nitric oxide (NO) and Hydrogen Peroxide (H2O2) radical scavenging assay. Nine compounds are crystallized in monoclinic space group with four compounds in P21/c, three compounds in P21/n and two compounds in Cc and Pc. Another, two compounds are crystallized in triclinic space group š1Ģ
and one in orthorhombic space group Pbca. All the chalcone molecules are constructed by two individual rings which are interconnected by a C=CāC(=O)āC enone bridge and form a trans configuration with respect to the C=C double bond. The majority of the compounds is adopted to a nearly-planar conformation except compound (E)-1-(5-chlorothiophen-2-yl)-3-mesitylprop-2-en-1-one (1e) and (E)-3-(5'-bromo-[2,2'-bithiophen]-5-yl)-1-(5-chlorothiophen-2-yl)prop-2-en-1-one (1g). Two molecular structures, (E)-1-(5-chlorothiophen-2-yl)-3-(thiophen-2-yl)prop-2-en-1-one (1b) and (E)-1-(5-chlorothiophen-2-yl)-3-(4-(trifluoromethyl)phenyl)prop-2-en-1-one (1h) are disordered structure. All compounds exhibit both conventional and non-conventional hydrogen bonds except compounds (E)-1-(5-chlorothiophen-2-yl)-3-(4-(methylthio)phenyl)prop-2-en-1-one (1d) and (E)-1-(5-chlorothiophen-2-yl)-3-(4-(trifluoromethoxy)phenyl)prop-2-en-1-0one (1i). Based on the antioxidant inhibition results, it shows that compounds (E)-1-(5-chlorothiophen-2-yl)-3 (pyridin-2-yl)prop-2-en-1-one (1a) and (E)-1-(5-chlorothiophen-2-yl)-3-(4-(methylthio)phenyl)prop-2-en-1-one (1d) are active toward FIC assay. Meanwhile, compound (E)-1-(5-chlorothiophen-2-yl)-3-(4-(methylthio)phenyl)prop-2-en-1-one (1d) shows higher chelating power than the standard drugs (EDTA) in IC50 test.
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Physics