Uronic acids synthesis

An additional possibihty for uronic acid synthesis is the reduction of monolactones of the corresponding aldaric acids ... 

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... 

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... 

The most efficient photosubstitution reaction, with many applications in synthesis, is the photobromination method developed by FERRIER s group [24]. The substitution of H-5 is regioselective and stereoselective for pentopyranosides [25], hexo-pyranosides [26], 1-6 anhydrosugars [27], uronic acids [24, 28] heterocyclic derivatives from deoxyinosones [29], nucleosides [30, 31], etc.. . using bromine or N-bromo-succinimide in carbon tetracloride under irradiation. 

Most of the known oligoglycuronic acids are aldobiouronic acids. Because of the stability of the glycosidic linkage of aldobiouronic acids toward acid hydrolysis, they are readily isolated after vigorous hydrolysis of polysaccharides that contain uronic acid residues. They have been obtained from wood hemicelluloses, plant mucilages, gums, bacterial and animal polysaccharides, and by synthesis. 

V. A. Timoshchuk, Transformation of uronic acids catalysed boron trifluoride etherate. Synthesis of 4-O-acetyl-1,2-isopropy lidene-3-O-toluene-p-sulphonyl-a-D-xylopyranurono-5,1-lactone, Carbohydr. Res., 145 (1985) 131-134. 

P. Kovac, J. Hirsch, and V. Kovacik, Synthesis and reactions of uronic acid derivatives. Part II. /8-Elimination reactions of some derivatives of methyl-3,4-0-isopropylidene-D-galacturonate, Carbohydr. Res., 32 (1974) 360-365. 

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