Nuclear Magnetic Resonance Spectroscopic Analysis of Gossypol and Its Analogs in Cotton Flower Buds (Gossypium)

1978 ◽  
Vol 61 (1) ◽  
pp. 146-149
Author(s):  
Anthony C Waiss ◽  
Bock G Chan ◽  
Mabry Benson ◽  
Maurice J Lukefahr
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Spectroscopic Analysis ◽  
Internal Standard ◽  
Aromatic Proton ◽  
Flower Bud ◽  
Chemical Structures ◽  
Magnetic Resonance Spectroscopic Analysis ◽  
Proton Peak ◽  
Nuclear Magnetic

Abstract A specific nuclear magnetic resonance (NMR) method has been developed for determining gossypol and its analogs in the cotton flower bud. Gossypol and its related analogs, some of whose chemical structures have not yet been determined, can be identified by the distinctive NMR absorption of the aldehydic protons between 10.0 and 11.3 ppm. These compounds are quantitatively estimated by comparing the areas of the aldehydic proton absorptions with the aromatic proton peak (6.82 ppm) from p-dimethoxybenzene internal standard.

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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