Synthesis and bioactivity studies of coumarin and its derivatives

摘要: Coumarin is a naturally occurring compounds being present in several plants and also can be produced through organic synthetic reactions. In this study, substituted coumarins of 3-acetylcoumarin, 3-acetyl-7-(diethylamino)coumarin, 7-(diethylamino)-3-(1-oxobutyl)coumarin, 3-oxobutyl-3H-naphtho[2,1-b]pyran-2- one, 6-bromo-3-(1-oxobutyl)coumarin 8-methoxy-3-(1-oxobutyl)coumarin were synthesized via Knoevenagel condensation reaction respective 2-hydroxybenzaldehyde derivatives with active methylene group from ethyl acetate or butyrylacetate under basic condition. Meanwhile, 7-hydroxy-4-methylcoumarin, 4-methyl-2H-benzo[h]chromen-2-one, 7-hydroxy-4,8-dimethylcoumarin, 7-hydroxy- 4-propylcoumarin, 4-propyl-2H-benzo[h]chromen-2-one, 7-hydroxy-8-methyl-4- propylcoumarin 7,8-dihydroxy-4-propylcoumarin prepared Pechmann by the phenol s-keto-ester presence sulphuric acid as catalyst. Futher methylation on 7-hydroxy-4-methylcoumarin iodomethane catalysed K2CO3 gave 7-methoxy-4-methylcoumarin. Modification hydroxyl using butyric anhydride dry pyridine yielded 7,8-bis-(1-oxobutoxy)-4-propylcoumarin. addition, 7-hydroxy-4,8-dimethylcoumarin was converted to 7-benzyloxy-4,8-dimethylcoumarin benzyl chloride acetone. 7,8-methylenedioxy-4-propylcoumarin undergoes Williamson etherification which involved SN2 mechanism between secondary alkyl halide potassium salt phenoxide. All characterized spectroscopic techniques infrared (IR), proton carbon nuclear magnetic resonance (1H 13C NMR), mass spectrometry (MS). The tested for their antioxidant antibacterial activities. It found that hydroxylated coumarin positive towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay IC50 value 4.09 ?g/mL while other inactive. activity show 6-bromo- 3-(1-oxobutyl)coumarin exhibited strong agent against B. subtilis bacteria MIC 56.25 ?g/mL. 7,8-Methylenedioxy-4-propylcoumarin showed all Gram-positive bacteria.