The antioxidant activity of new coumarin derivatives.
The antioxidant activity of two synthesized coumarins namely, N-(4,7-dioxo-2- phenyl-1,3-oxazepin-3(2H,4H,7H)-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 5 and N-(4-oxo-2-phenylthiazolidin-3-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 6 were studied with the DPPH, hydrogen peroxide and nitric oxide radical methods and compared with the known antioxidant ascorbic acid. Compounds 5 and 6 were synthesized in a good yield from the addition reaction of maleic anhydride or mercaptoacetic acid to compound 4, namely N'-benzylidene-2-(2-oxo-2H-chromen-4-yloxy)acetohydrazide. Compound 4 was synthesized by the condensation of compound 3, namely 2-(2-oxo-2H-chromen-4-yloxy) acetohydrazide, with benzaldehyde. Compound 3, however, was synthesized from the addition of hydrazine to compound 2, namely ethyl 2-(2-oxo-2H-chromen-4-yloxy)acetate, which was synthesized from the reaction of ethyl bromoacetate with 4-hydroxycoumarin 1. Structures for the synthesized coumarins 2-6 are proposed on the basis of spectroscopic evidence.
Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, Malaysia; E-Mails:  amir@eng.ukm.my  (A.A.H.K.);  ahmedym@eng.ukm.my  (A.Y.M.);  drab@eng.ukm.my (A.B.M.).
Abdul Amir H
AA
Kadhum
Ahmed A
AA
Al-Amiery
Ahmed Y
AY
Musa
Abu Bakar
AB
Mohamad
D000975:Antioxidants / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D003198:Computer Simulation; D003374:Coumarins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D005609:Free Radicals / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010851:Picrates / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism
D000975:Antioxidants; D001713:Biphenyl Compounds; D003374:Coumarins; D016166:Free Radical Scavengers; D005609:Free Radicals; D010851:Picrates; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; C004931:1,1-diphenyl-2-picrylhydrazyl; D001205:Ascorbic Acid