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Baeckeins A and B, Two Novel 6‐Methylflavonoids from the Roots of Baeckea frutescens
Author(s) -
Jia BeiXi,
Yang Jie,
Chen XiaoQing,
Cao Yuan,
Lai MaoXiang,
Wang Qiang
Publication year - 2011
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201100176
Subject(s) - chemistry , heteronuclear single quantum coherence spectroscopy , stereochemistry , ring (chemistry) , two dimensional nuclear magnetic resonance spectroscopy , organic chemistry
A pair of novel isomeric 6‐methylflavonoids, named baeckeins A ( 1 ) and B ( 2 ), were isolated from the roots of Baeckea frutescens. The two compounds possess a unique C 23 skeleton, resulting from the 6‐methylation and 8‐arylation of a flavonol (=3‐hydroxy‐2‐phenyl‐4 H ‐1‐benzopyran‐4‐one) framework and the formation of an unusual lactone ring E. Their structures were elucidated by detailed spectroscopic analyses, including HR‐ESI‐MS and 1D‐ and 2D‐NMR data (HSQC, HMBC, and ROESY). A plausible biogenetic pathway for compounds 1 and 2 is also proposed ( Scheme ).