A convergent synthesis of carbohydrate-containing dendrimers

Abstract

The synthesis of carbohydratecontaining dendrimers has been achieved by a convergent growth approach. The synthetic strategy involves: 1) the synthesis of the triglucosylated derivative of tris(hydroxymethyl)methylamine (TRIS), 2) the introduction of a glycine-derived spacer and 3,3'-iminodipropionic acid derived branching units on to the TRIS derivative by amide bond formation, 3) condensation of the above saccharidecontaining dendrons with a trifunctional 1,3,5-benzenetricarbonyl derivative, used as the core, by formation of amide bonds, and 4) deprotection of the saccharide units. A 9-mer and an 18-mer, carrying nine and eighteen saccharide units at the periphery, respectively, have been synthesized, in high yields at each step, by this synthetic strategy. By a variety of chromatographic and spectroscopic techniques, the dendrimers were shown to be structurally homogeneous, monodisperse, and error-free at all steps in their growth. These investigations were complemented by molecular modeling studies on the dendrimers. The presence of slightly distorted C₃ symmetry was noted in both the 9-mer and the 18-mer.