Uronic synthesis

Much of the chemistry of monosaccharides is the familiar chemistry of alcohols and aldehydes/ketones. Thus, the hydroxyl groups of carbohydrates form esters and ethers. The carbonyl group of a monosaccharide can be reduced with NaBH4 to form an alditol, oxidized with aqueous Br2 to form an aldonic acid, oxidized with HNO3 to form an aldaric acid, oxidized enzymatically to form a uronic acid, or treated with an alcohol in the presence of acid to form a glycoside. Monosaccharides can also be chain-lengthened by the multistep Kiliani-Fischer synthesis and can be chain-shortened by the Wohl degradation. 

Synthesis of Uronic Acids. Part II. 2 3 4-Trimethyl Derivatives of Mannuronic, Glucuronic, and Galacturonic Acids, F. Smith, M. Stacey, and P. I. Wilson, J. Chem. Soc., (1944) 131-134. 

In the absence of suitable cell wall mutants, DCB-adapted tomato cells provide an opportunity to characterise the pectin network of the plant cell wall. It should be noted that synthesis and secretion of hemicellulose is not inhibited but, in the absence of a cellulose framework for it to stick to, most of the xyloglucan secreted remains in soluble form in the cells culture medium (9, 10) while other non-cellulosic polysaccharides and other uronic-acid-rich polymers predominate in the wall. 

Fig. 1. Promotion of ethylene synthesis by MG pericarp discs following treatment with water or varying concentrations (uronic acid equivalents) of B fruit water soluble fraction. Bars indicate SEs for the means of measurements of sets of 8 discs/teatment fr wt, Fresh weight.

A similar protocol was used by Prof. Gervay-Hage in a recent synthesis of uronic acids (Scheme 17).40... 

The synthesis of L-ribofuranose derivatives from 16a has been carried out by Walker and Hogenkamp (35). The procedure involves oxidation of the hydroxymethyl group of 16a with dimethyl sulfoxide N,N dicyclohexylcarbodiimide and acid hydrolysis of the protecting group to give L-riburonic acid, which was converted into methyl (methyl a,/ -ribofurano-sid)uronates (26). Reduction of 26 with sodium bis(2-methoxyethoxy)alu-minum hydride gave the chromatographically separable anomers of methyl L-ribofuranoside (27). 

Synthesis of GAGs requires the sequential attachment of an jV-acetyl amino sugar or uronic acid to the protein core molecule (Figure 9.2), each step being catalysed by a... 

The occurrence of uronic acid provides another means of easy access to bicyclic lactones, which can be used for the synthesis of various targets, such as surfactants or pseudo glycopeptides. 

Omori T (1996) Substitution Reactions of Technetium Compounds. 176 253-274 Oscarson S (1997) Synthesis of Oligosaccharides of Bacterial Origin Containing Heptoses, Uronic Acids and Fructofuranoses as Synthetic Challengers. 186 171-202 Ostrowicky A, Koepp E, Vogtle F (1991) The Vesium Effect Synthesis of Medio- and Macrocyclic Compounds. 161 37-68 Otsuji Y,see Mizuno K (1994) 169 301-346 Pdlinkd I, see Tasi G (1995) 174 45-72... 

Synthesis of Oligosaccharides of Bacterial Origin Containing Heptoses, Uronic Acids and Fructofuranoses as Synthetic Challenges... 

This promising method has so far been used mainly for the synthesis of common hexosyl derivatives, but it has been extended to uronic acid320 and deoxy sugar263 derivatives and found to be efficient. 

S. S. Thomas, J. Plenkiewicz, E. R. Ison, M. Bols, W. Zou, W. A. Szarek, and R. Kisilevsky, Influence of monosaccharide derivatives on liver cell glycosaminoglycan synthesis 3-deoxy-D-xylo-hexose (3-deoxy-o-gaIactose) and methyl (methyl 4-chloro-4-deoxy- 3-D-galacto-pyranosid)uronate, Biochim. Biophys. Acta 1272 37 (1995). 

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