Synthesis of centose and two isomeric d-glucose trisaccharides

Abstract

Condensation of tetra- O-acetyl-α- d-glucopyranosyl bromide with 1,3,6,2′,3′,4′,6′-hepta- O-acetyl-β-maltose in acetonitrile containing mercuric cyanide and mercuric bromide, gave the hendecaacetates of O-α- d-glucopyranosyl-(1→4)- O-[α- d-glucopyranosyl-(1→2)]-β- d-glucopyranose (β-centose) (21.3%) and the β- d-(1→2)-linked isomer (14.4%). The main condensation product (18.4%) obtained from the anomerically unsubstituted β-maltose heptaacetate was identified tentatively as the hendecaacetate of O-α- d-glucopyranosyl-(1→4)-β- d-glucopyranosyl α- d-glucopyranoside.