6S,8R-Stereochemistry of the C27- and C29-alkane-6,8-diols isolated from three compositae flowers.
The Deltadelta (deltaS-deltaR) values for the C-1 methyl 1H signals in the 1H-NMR spectroscopy of the bis-MTPA esters of four synthetic stereoisomers of alkane-6,8-diols, viz., bis-MTPA esters of (6S,8R)-C27- (1a) and C29- (3a) (Deltadelta = -0.05 ppm), (6R,8S)-C27- (2a) and C29- (4a) (Deltadelta = +0.05 ppm), (6S,8S)-C27- (5a) (Deltadelta = -0.01 ppm), and (6R,8R)-C27- (6a) (Deltadelta = +0.01 ppm) alkane-6,8-diols, made it possible to differentiate unequivocally among the four stereoisomers. This allowed the determination of the (6S,8R)-stereochemistry (Deltadelta = -0.05 ppm for the bis-MTPA esters) for the natural C27- and C29-alkane-6,8-diols isolated from the flowers of three Compositae plants, Carthamus tinctorius, Cynara cardanclus, and Taraxacum platycarpum.
Ukiya
M
M
College of Science and Technology, Nihon University, Tokyo, Japan.
Akihisa
T
T
Motohashi
S
S
Yasukawa
K
K
Kimura
Y
Y
Kasahara
Y
Y
Takido
M
M
Tokutake
N
N
D000473:Alkanes / Q000737:chemistry*; D019659:Asteraceae / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism
D000473:Alkanes