ABSTRACT
A facile, convenient and high yielding synthesis of a combinatorial library of 3-alkanoyl/aroyl/heteroaroyl-2H-chromene-2-thiones has been developed by the condensation of easily accessible beta-oxodithioesters and salicylaldehyde/substituted 2-hydroxybenzaldehydes under solvent-free conditions. The assessment of radical scavenging capacity of the compounds towards the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was measured and these compounds were found to scavenge DPPH free radical efficiently. Five selected compounds were able to protect curcumin from the attack of sulfur free radical generated by radiolysis of glutathione (GSH). The newly synthesized compounds exhibited profound antioxidant activities. Five of them rendered comparatively high antioxidant capacity.
Subject(s)
Free Radical Scavengers/chemistry , Free Radical Scavengers/chemical synthesis , Thiones/chemistry , Thiones/chemical synthesis , Biphenyl Compounds/chemistry , Curcumin/chemical synthesis , Curcumin/chemistry , Curcumin/pharmacology , Free Radical Scavengers/pharmacology , Picrates/chemistry , Sulfur/chemistry , Thiones/pharmacologyABSTRACT
A facile route to hitherto unknown 5-methylmercaptothiocarbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones and substituted 2H-chromene-2-thiones has been developed. SnCl(2)-catalyzed cyclocondensation of beta-oxodithioesters with a variety of readily accessible aldehydes and urea affords the dihydropyrimidinones. The methodology involves the three-component Biginelli reaction. On the other hand, substituted salicylaldehyde and beta-oxodithioesters reacted under the same condition to afford the substituted 2H-chromene-2-thiones in high yields.
