Synthesis of Oligosaccharide Dendrimers

Abstract

Two b-d-glucopyranosidebased dendrimers, one incorporating three tetra-and the other three heptasaccharide wedges attached to a central trisfunctionalized nonsaccharide core component, have been synthesized. Branching at designated saccharide units of the tetra-and of the heptasaccharide wedges arises from (1 32)/ (1 33)/(1 36) and from (1 33)/(1 36) intersaccharide linkages, respectively, with the 1,2-trans configuration at all anomeric centers. Both oligosaccharide wedges were constructed by stepwise glycosylation strategies and have reactive primary amino groups at their focal points located at the termini of spacer arms connected to the reducing glucose residues. Amide bond formation between these amino groups and appropriate core components carrying three carboxylic acid functions afforded two dendrimers incorporating a total of 12 and 21 monosaccharide units when the tetra-and the heptasaccharide wedges were employed, respectively. These nanosized highly branched macromolecules possess molecular diameters of 5 ± 6 nm and molecular weights of 6195 and 10 008 Daltons for the 12-mer and 21-mer, respectively. The wedges and dendrimers were characterized and the intersaccharide connectivity elucidated by extensive mono-and bidimensional 1 H and 13 C NMR spectroscopic investigations. In addition, LSIMS and MAL-DI-TOFMS investigations were also performed and revealed molecular ion peaks generally as H, Na, or K adducts for all oligosaccharides.

Convergent Dendrons and Dendrimers: from Synthesis to Applications

“…A wide variety of other convergent syntheses have been developed for the preparation of dendritic poly(amides), 132,153-160 poly(esters), 161,162 poly-(urethanes), 163,164 poly(carbonates), 165 poly(aryl ethers), [166][167][168][169] poly(arylamines), [170][171][172][173] poly(aryl ketones), 174 poly(aryl alkynes), 175 poly(aryl methanes), 176 poly(arylammonium) salts, 177 poly (thioureas), 178 poly-(ether imides), 179 poly(keto ethers), [180][181][182] poly(amine ethers), 183 poly(amino esters), 184 poly(amide ethers), [185][186][187][188][189] poly(pyridyl amides), 190 poly(uracils), 191 poly(triazenes), 192,193 poly(saccharides), 194 poly(glycopeptides), 195 and poly(nucleic acids). 196 In addition, chiral dendrimers 197,198 including amide, [199][200][201] ether, 96-108 and ester 202 linkages, and organometallic dendrimers, [203][204][205][206][207] including silicon, 208 germanium, 209 palladium, 210 and platinum 211-214 containing rep...…”

Synthesis of Hyperbranched Carbohydrate Polymers by Ring‐Opening Multibranching Polymerization of Anhydro Sugar

“…For a spherical polymer with many terminal sugar residues, there are a few types of glycodendrimers, for example, dendrimers prepared from the reaction of the dendrimer surface with monosaccharides and disaccharides, [23][24][25][26][27][28][29] and dendrimers prepared through the convergent method using semidendritic branched oligosaccharides. [30][31][32] Although the synthesis of such glycodendrimer types was accomplished, dendrimers essentially consisting of sugar units, that is, dendritic carbohydrate polymers, have not been prepared…”

Improved Routes for the Preparation of Pentaerythritol Mono‐O‐benzyl Ether

“…[32,33] The most commonly used conditions for acid hydrolysis are reflux in 80% aqueous AcOH, [34] stirring with 90% aqueous CF 3 CO 2 H acid in CH 2 Cl 2 at room temperature, [35] and reaction with 1% I 2 in CH 3 OH (w/v) at room temperature or at reflux. [36] Unfortunately, none of these methods work efficiently for the hydrolysis of the diasteroisomeric mixture 6a and 6b.…”