The Study On Intramolecular Cyclaization Induced By Metal Zinc And The Synthesis Coumarin Derivatives In Water Medium

The coumarin and its derivatives play an important role in organic synthesis and in the nature, but the intramolecular cyclaization induced by zinc in water medium by Reformatsky reaction to synthesize courmarin were little reported. To get the optimized condition, the effect of solvent, the reaction tempeture and the reaction time were examined. the coumarin derivatives was synththetized starting from 3-methyl phenol and ethyl acetoacetate, 7-bromomethyl-4-methyl-courmarin was obtained via bromization , Barbier-type reactions of the compound bromide with aldehyde in water media occurred to afford the coumarin derivativesA possible additional mechanism was proposed about coumarin cyclaization. We found the reaction may be undergo a transition state of six-mumbered ring through the nucleophilic addition reaction...