ABA- and BAB-triblock cooligomers of tri-O-methylated and unmodified cello-oligosaccharides: syntheses and structure-solubility relationship

Triblock cooligomers consisting of tri-O-methyl-glucopyranosyl and unmodified glucopyranosyl residues, methyl 2,3,4,6-tetra-O-methyl-beta-d-glucopyranosyl-(1 -> 4)-2,3,6-tri-O-methyl-beta-d-glucopyranosyl-(1 -> 4)-beta-d-glucopyranosyl-(1 -> 4)-beta-d-glucopyranosyl-(1 -> 4)-2,3,6-tri-O-methyl-beta-d-glucopyranosyl-(1 -> 4)-2,3,6-tri-O-methyl-alpha-d-glucopyranoside (1: ABA triblock cooligomer; DS = 2.1) and beta-d-glucopyranosyl-(1 -> 4)-2,3,6-tri-O-methyl-beta-d-glucopyranosyl-(1 -> 4)-2,3,6-tri-O-methyl-beta-d-glucopyranosyl-(1 -> 4)-2,3,6-tri-O-methyl-beta-d-glucopyranosyl-(1 -> 4)-2,3,6-tri-O-methyl-beta-d-glucopyranosyl-(1 -> 4)-d-glucopyranose (2: BAB triblock cooligomer; DS = 1.8) were prepared. Compound 1 dissolved both in distilled water and chloroform but compound 2 dissolved in distilled water not in chloroform, though compounds 1 and 2 consist of 4 tri-O-methyl-glucopyranosyl and 2 unmodified anhydro glucopyranosyl units.