Synthesis of pentasaccharide and heptasaccharide derivatives and their effects on plant growth.

Two oligosaccharide derivatives, beta-D-Glcp-(1-6)-beta-D-Glcp-(1-6)-beta-D-Glcp-(1-6)-beta-D-Glcp-(1-4)-alpha-D-ManpOMe (1) and beta-D-Glcp-(1-6)-beta-D-Glcp-(1-6)-beta-D-Glcp-(1-6)-beta-D-Glcp-(1-6)-beta-D-Glcp-(1-6)-beta-D-Glcp-(1-4)-alpha-D-ManpOMe (2), have been synthesized efficiently using a convergent glycosylation strategy of 2 + 3 and 2 + 5. 1,6-Anhydro-beta-D-glucopyranose, which was prepared from cotton pyrolysis, was applied as a key synthon in the synthesis, significantly simplifying the preparation. The bioassay suggested that these two oligosaccharides can both stimulate the growth of maize cultured in liquid medium at a concentration of 3 ppm.