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Total NMR assignments of new [C 7 OC 7″ ]‐biflavones from leaves of the limonene–carvone chemotype of Lippia alba (Mill) N. E. Brown
Author(s) -
Barbosa Francisco Geraldo,
Lima Mary Anne Sousa,
Silveira Edilberto Rocha
Publication year - 2005
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1546
Subject(s) - chemotype , chemistry , carvone , two dimensional nuclear magnetic resonance spectroscopy , biflavonoids , stereochemistry , limonene , phytochemical , terpene , carbon 13 nmr , essential oil , chromatography , biochemistry
Phytochemical analysis of leaves of the limonene–carvone chemotype of Lippia alba led to the isolation of two biflavonoids with a new structural pattern with an ether linkage: 5,5″‐dihydroxy‐6,4′,6″,3″′,4″′‐pentamethoxy‐[C 7 OC 7″ ]‐biflavone ( 1 ) and 4′,4,5,5″‐tetrahydroxy‐6,6″,3″′‐trimethoxy‐[C 7 OC 7″ ]‐biflavone ( 2 ). Structural elucidation of the new compounds was established on the basis of spectral data, through the use of 1D NMR and several 2D shift correlated NMR pulse sequences (COSY, HMQC, HMBC and NOESY). Copyright © 2005 John Wiley & Sons, Ltd.