ellagic acid derivative of tannin isolated from plant and process for synthesizing it

摘要

PURPOSE: Provided is a method for synthesizing ellagic acid derivatives from tannin and polyphenol extracted from Castanea crenata Sieb. et. Zucc., Diospyros kaki Thunberg, Pinus densiflora Sieb. et Zucc., and Humulus Lupulus. Synthesized ellagic acid derivatives of the invention is effective in whitening skin, eliminating toxicity of bacteria and free radicals of activated oxygen, restraining tumor, and restraining DNA. CONSTITUTION: The ellagic acid derivatives£2-(2-carboxy-trihydroxy phenyl)-3, 4, 5-trihydroxy methyl benzonate)|are prepared by the processes of (i) reacting a starting compound described below formulae with benzyl chloride for protecting -OH radicals; (ii) reacting the prepared compound in the first step with benzyl bromide/NaOH at the same time; and then (iii) reacting the prepared compound in the second step with methyl iodine/palladium as catalysts. In the formulae, R represents a lower alkyl group having 1 to 5 of carbon number and a higher alkyl group having 6 to 18 of carbon number.