Synthesis of Functionalized Thiodisaccharides by Conjugate Addition

Oligosaccharides containing thioglycosidic linkages are resistant to enzyme-catalysed hydrolysis and therefore interesting material for studies of carbohydrate hydrolases. Some of these were shown to be competitive inhibitors for several glycanases such as α-amylase,1 cellobiohydrolase I and II,2 and for α-l-fucosidase,3 a glycosidase. Thio-oligosaccharides have also been used to prepare column material for affinity chromatography to isolate carbohydrate hydrolases. In contrast, affinity material containing normal O-glycosidic bonds was hydrolysed and led to column deterioration. By employing this approach, affinity materials containing 1,4-dithiocellobiose and 1,4,4′-trithiocellotriose could be used successfully to separate the cellobiohydrolases of Trichoderma reesei.2