4,6-Dimethoxy-1,3,5-triazin-2-yl β-D-glycosaminides: Novel Substrates for Transglycosylation Reaction Catalyzed by Exo-β-D-glucosaminidase from Amycolatopsis orientalis

A novel sugar adduct, 4,6-dimethoxy-1,3,5-triazin-2-yl beta-D-glucosaminide (GlcN-beta-DMT), has been prepared by the reaction of D-glucosamine (GlcN) and 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-morpholinium chloride (DMT-MM). The adduct was recognized by exo-beta-D-glucosaminidase (GlcNase) from Amycolatopsis orientalis and transferred the GlcN moiety, giving rise to the corresponding glucosaminides. This chemo-enzymatic process was successfully applied to D-galactosamine (GalN). GalN-beta-DMT prepared directly from GalN and DMT-MM behaved as an efficient glycosyl donor for transfer of the GalN moiety catalyzed by the same enzyme. The introduction of the 4,6-dimethoxy-1,3,5-triazin-2-yl leaving group to the anomeric center significantly enhanced transglycosylating ability, resulting in the efficient glycosidase-catalyzed synthesis of glycosaminides.