A new mechanism for oxidation of epigallocatechin and production of benzotropolone pigments

被引:65
作者
Matsuo, Y [1 ]
Tanaka, T [1 ]
Kouno, I [1 ]
机构
[1] Nagasaki Univ, Grad Sch Biomed Sci, Nagasaki 8528521, Japan
基金
日本学术振兴会;
关键词
D O I
10.1016/j.tet.2006.03.021
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Enzymatic oxidation of (-)-epigallocatechin gave two new quinone dimers, dehydrotheasinensin C and proepitheaflagallin. Dehydrotheasinensin C has a hydrated cyclohexenetrione structure and its oxidation-reduction dismutation reaction yielded black tea polyphenols, theasinensins C and E, and desgalloyl oolongtheanin. The structure of proepitheaflagallin was determined based on spectroscopic data of its quinoxaline derivatives prepared by condensation with o-phenylenediamine. Proepitheaflagallin was decomposed on heating to give epitheaflagallin and hydroxytheaflavin. The former is a known black tea pigment and the latter is a new pigment with 1',2,3'-trihydroxy-3,4-benzotropolone moiety. The results revealed a new mechanism for the production of these pigments from epigallocatechin. (c) 2006 Elsevier Ltd. All rights reserved.
引用
收藏
页码:4774 / 4783
页数:10
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