1H Diffusion-Ordered Nuclear Magnetic Resonance Spectroscopic Analysis of Water-Extractable Arabinoxylan in Wheat (Triticum aestivum L.) Flour

2021 ◽  
Vol 69 (13) ◽  
pp. 3912-3922
Author(s):  
Wannes L. De Man ◽  
Ewoud Vaneeckhaute ◽  
Niels De Brier ◽  
Arno G. B. Wouters ◽  
Johan A. Martens ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Triticum Aestivum ◽  
Magnetic Resonance ◽  
Spectroscopic Analysis ◽  
Triticum Aestivum L ◽  
Magnetic Resonance Spectroscopic Analysis ◽  
Water Extractable ◽  
Nuclear Magnetic

Stereochemistry of acid-catalyzed cleavage of 7-chloro-1-methylnortricyclene in deuterated medium; evidence for edge protonation of nortricyclenes

1980 ◽  
Vol 58 (16) ◽  
pp. 1725-1737 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
Frank Peter Cappelli
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Spectroscopic Analysis ◽  
Methyl Group ◽  
Magnetic Resonance Spectroscopic Analysis ◽  
Acid Catalyzed ◽  
Nuclear Magnetic

Cleavage of 7-chloro-1-methylnortricyclene (1e) in D2SO4–DOAc yields deuterated syn-7-chloro-1-methyl-exo-2-norbornyl acetate (3a-d) (1.04 excess d per molecule) and deuterated anti-7-chloro-1-methy l-exo-2-norbornyl acetate (3b-d) (1.28 excess d per molecule) as the kinetic products. 1H and 2H nuclear magnetic resonance spectroscopic analysis of the corresponding alcohols complexed with Eu(fod)3 shows that deuterium is located endo at C-6 and in the methyl group of the syn-7-chloroacetate, endo at C-6 and C-2, at C-7, and in the methyl group of the anti-7-chloroacetate. That the deuterium at C-6 of both acetates is 80–90% stereochemically pure endo, in our view, establishes that the bond farthest removed from the electron-withdrawing chlorine is preferentially cleaved via edge deuteronation.

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