Production of glucosamine containing disaccharides of the Lewis-A and -X types employing glycosidases

Disaccharide derivatives of interest for inhibition studies and for synthesis of the blood group determinants Lewis-a and Lewis-x were obtained with glycosidases as catalysts. Thus, Fucα(1–4)(6-OBn)GlcNH2βSEt and Galβ1–3(6-OBn)GlcNH2β-SEt were produced employing (6-OBn)GlcNH2βSEt as acceptor and α-L-fucosidase and β-D-galactosidase, respectively, as catalysts. The phthalimido derivative of lactosamine, Galβ1-4GlcNPhthβSEt, was prepared from lactose employing GlcNPhthβSEt as the acceptor and a yeast β-galactosidase as catalyst. The reactions were both regio- and stereospecific, which allowed straightforward production of pure products on a g scale and higher.