Aldonic acids polymerization

Several 0-protected aldonic acids and aldonolactones such as 16-21 have been used as monomers in polycondensation and ring opening polymerization reactions [32-34],... 

Pfannemtiller et al. showed that it is possible to obtain carbohydrate-containing amphiphiles with various alkyl chains via amide bond formation. For this, mal-tooligosaccharides were oxidized to the corresponding aldonic acid lactones, which could subsequently be coupled to alkylamines [128-136]. Such sugar-based surfactants are important industrial products with applications in cosmetics, medical applications etc. [137-139]. The authors were also able to extend the attached mal-tooligosaccharides by enzymatic polymerization using potato phosphorylase, which resulted in products with very interesting solution properties [140, 141]. 

The first surface-initiated enzymatic polymerization reported was the synthesis of amylose brushes on planar and spherical surfaces [145]. For this, silica or silicone surfaces were modified with self-assembled monolayers of (3 amino-propyl)trimethoxysilane or chlorodimethylsilane, respectively. To these functionalities, oligosaccharides were added via (a) reductive amidation of the oligosaccharides to surface-bound amines, (b) conversion of the oiigosaccharide to the according aldonic acid lactone and reaction with surface bound amines, and (c) incorporation... 

After conversion of the reducing end-groups in laminaran to aldonic acid residues by bromine oxidation. Smith and coworkers were able to separate the acidic from the neutral components on an ion-exchange resin. From the amounts of formaldehyde formed on periodate oxidation, the degree of polymerization of the two fractions was estimated as 17 and 28, respectively. The neutralization equivalent and the mannitol content gave values of 15 and 31, respectively. 

In addition to lactone formation, it is probable that extramolecular esterification may take place with the formation of aldonic esters of aldonic acids (e.g., gluconic acid gluconate) and chain polymerization also may occur. In such systems, the concentration of water present would be expected to exert a profound influence on the composition of the equilibrium solution. Lactic acid forms external esters (lactides), but this type of condensation through carboxyls and a-hydroxyls has not been observed for hexonic and pentonic acids. 

Aliphatic polyesters may be classified into two groups, depending on the bond constitution of the monomCTs poly(hydroxy acid)s i.e. polyhydroxyalkanoates (PHAs)) and polyfalkylene dicarboxylate)s [68]. The former are polymers of hydroxy acids (a, p,...(i)-hydroxy acids), obtained by ring-opening polymerization or polycondensation reactions. The latter are S3uithesized by the polycondensation reaction of diols with dicarboxylic acids. Aldonic and aldaric acids can be used to prepare both groups of polyesters. 

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