Preparation of a sulfated linear (1->4)-beta-D-galactan with variable degrees of sulfation

A linear 1,4-beta-D-galactan has been prepared by partial acid hydrolysis of the major lupin seed polysaccharide on a preparative scale. The galactan has been characterized by acetylation and methylation analysis, by GPC, as well as by its 1H- and 13C-NMR-spectra. Sulfation with increasing amounts of SO3-pyridine yielded a series of galactan sulfates with increasing DS. In all derivatives, the sulfate groups had a similar pattern of distribution, as shown by methylation analysis. Beside unsulfated parts of the molecule, there were also parts with a multiple substitution pattern.