A study of 13CH coupling constants in hexopyranoses

Proton decoupled and undecoupled 13C n.m.r. spectra have been measured on a number of hexopyranoses. The direct coupling constants between the anomeric carbon atoms and protons {1J[13C–H(1)]} were found to be ca. 160 in the β-anomers and ca. 170 Hz in the α-anomers; the difference of ca. 10 Hz between pairs of anomers was found in almost all cases. Chemical shifts and 1J(13CH) values of the other carbon atoms in the pyranose rings were also measured.