13C-nuclear magnetic resonance (NMR) spectra of O-acylglucoses. Additivity of shift parameters and its application to structure elucidations.

Abstract

CMR spectra of all positional isomers of mono-O-myristoyl-α- and β-D-glucopyranoses in pyridine-d5 are reported and discussed in connection with the anomalies of 1α- and 1β-O-acyl derivatives. Calculation of the chemical shifts of some dimyristates using the acylation shifts obtained from monomyristate (Table III) gave values in agreement with the observed values for each compound, confirming the additivity of the acylation shift parameters. The effects of the solvent and the nature of the acyl moiety on the acylation shifts also examined using twenty samples, and it was concluded that the acylation shift parameters are independent of the solvent (s) and the kind (s) of acyl group (s), so that the above shift values obtained for the myristoyl group can be regarded as a universal set of additive parameters for usual di- and tri-acyl derivatives. This additivity rule of parameters was successfully applied to the structure elucidation of two naturally occurring acylglucose derivatives, tuliposide-A and spirarin. The previously reported data for various glucosyl γ-nitropropanoates in acetone-d5 are compared with the values calculated from the above parameters, again showing fair agreement.