Structure of Echivulgarine, a Pyrrolizidine Alkaloid Isolated from the Pollen of Echium vulgare.
1,2-Dehydropyrrolizidine alkaloids are common toxic metabolites isolated from plants within the Boraginaceae, in particular from the genera Heliotropium and Echium. Previous studies have deduced the structures of these often potent bioactives based upon mass spectrometric evidence, but these identifications have not established conclusive connectivity and configurational data. Herein, we describe the isolation and full structural characterization of echivulgarine, occurring in the pollen of Echium vulgare and correct the structure previously ascribed to the compound, using a comprehensive combination of both experimental and calculated nuclear magnetic resonance and electronic circular dichroism spectroscopic data.
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Eric
E
Cairns
School of Chemical & Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.
Muhammad Ali
MA
Hashmi
School of Chemical & Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.|Centre for Biodiscovery, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.
A Jonathan
AJ
Singh
School of Chemical & Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.|MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.
Galen
G
Eakins
School of Chemical & Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.|Centre for Theoretical Chemistry and Physics (CTCP), New Zealand Institute for Advanced Study, Massey University Auckland , Auckland, New Zealand.
Matthias
M
Lein
School of Chemical & Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.|Centre for Biodiscovery, Victoria University of Wellington , P.O. Box 600, Wellington 6140, New Zealand.
Robert
R
Keyzers
D002851:Chromatography, High Pressure Liquid; D036661:Echium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011058:Pollen / Q000737:chemistry; D011763:Pyrrolizidine Alkaloids / Q000737:chemistry* / Q000302:isolation & purification
D011763:Pyrrolizidine Alkaloids; C000606555:echivulgarine
DFT; absolute configuration; qNMR; structural reassignment