13C nuclear magnetic resonance spectra of glucobioses, glucotrioses, and glucans
Natural-abundance carbon-13 n.m.r. spectra of all the glucobioses and of four selected glucotrioses in aqueous solution have been measured and are discussed. Peak assignments were made on the basis of comparison with the spectra of methyl glucopyranosides, four mono-O-methylglucoses and five methyl glucobiosides. Carbon-13 n.m.r. spectroscopy proved to be a useful tool for stereochemical characterisation of these oligosaccharides. In addition, carbon-13 n.m.r. spectra of the β-limit dextrins from glycogen and amylopectin have been measured and the differences between them are discussed.