ISSN:
0749-1581
Keywords:
One-bond carbon-proton coupling constants
;
FPT INDO MO calculations
;
Oligosaccharides
;
Conformational effects
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A study is presented of the dependence on conformation of one-bond carbon-proton coupling constants in three 1-4-linked disaccharides. Calculated 1J(CH) values are based on the FPT formulation in the semi-empirical INDO MO method. The configuration at the anomeric carbon influences the 1J(CH) value, and the 1J(C-1′, H-1′) values are 20-30 Hz higher than the 1J(C-4, H-4) values. The conformational dependence of 1J(CH) on the dihedral angle about the C—O bonds is satisfactorily expressed in the analytical form 1J(CH) = A cos 2φ + B cos φ. The constants A-E are different for the α- and β-anomers. Calculated average values 〈1J(C-1′, H-1′)〉 = 163.7 Hz and 〈1J(C-4, H-4)〉 = 146 Hz for methyl β-xylobioside using PCILO-calculated abundances of conformers agree well with the experimental values of 162.7 and 147.5 Hz, respectively.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260281005
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