Synthesis and acid catalyzed hydrolysis of B2,5 type conformationally constrained glucopyranosides: incorporation into a cellobiose analogue

Isopropyl and p-nitrophenyl α- and β-d-glucopyranosides, restrained in a conformation close to B2,5 via an oxymethylene bridge have been synthesized. These four glucopyranosides were found to be hydrolyzed at similar rates, close to those observed for the parent unconstrained glucosides. In such derivatives, either α or β, the exocyclic cleaved bond is synperiplanar to an endocyclic oxygen lone pair. This conformationally locked glucopyranosyl moiety was also incorporated into a disaccharide, affording a conformationally restrained cellobiose analogue which was assayed against various glycosidases.