Of sugar acids

There are three possible classes of sugar acids which may be produced by the oxidation of monosaccharides (Figure 9.11). The aldonic acids are produced from aldoses when the aldehyde group at carbon 1 is oxidised to a carboxylic acid. If, however, the aldehyde group remains intact and only a primary alcohol group (usually at carbon 6 in the case of hexoses) is oxidised then a uronic acid is formed. Both aldonic and uronic acids occur in nature as intermediates in... 

Metabolism of sugars often involves dehydration to a,P-unsaturated carbonyl compounds. An example is the formation of 2-oxo-3-deoxy derivatives of sugar acids (Eq. 14-36). Sometimes a carbonyl group is... 

RF McFeeters, RL Thompson, HP Renting. Liquid chromatographic analysis of sugars, acids, and ethanol in lactic acid vegetable fermentations. J Assoc Anal Chem 67(4) 710-714, 1984. 

Three kinds of sugar acids can be formally obtained from the corresponding aldoses. They are aldonic acids, produced by oxidation at C-l of the aldose uronic acids, formed by oxidation of the primary alcohol group of the aldose and aldaric acids, formed by oxidation of both the aldehyde and the primary alcohol group. 

Amadori rearrangement, III, 42, 43 Amide rule of rotation, I, 21, 163 Amides, of sugar acids, oxidation of, III, 165... 

This behaviour ean be quahtatively explained by Equation (12.7) since 4>m increases as the width of the size distribution increases. A good example of the ef-feets that particles and polymers have on the rheological behavior of liquids is cloudy apple juice (Genovese and Lozano, 2000). The aqueous milieu of the juice is a solution of sugar, acids and salts (i.e., the clarified juice) that contains charged particles (0.25-5 pm in size) and pectin as a colloidal dispersion. The viscosity of cloudy apple juice has been described by the expression ... 

Strack, D., Keller, H., Weissenbock, G. (1987a) Enzymatic synthesis of hydroxycinnamic acid esters of sugar acids and hydroaromatic acids by protein preparations from rye (Secale cereale) primary leaves. /. Plant Physiol, 131, 61-73. 

There seems to be no limit to the types of pharmaceutical systems that can be isolated in the amorphous state. In the literature, samples of sugars, acids, bases, polymers, buffers, inorganics, salts, natural products, proteins, and low-molecular-weight APIs have all been reported to exist in an amorphous form. Likewise, pharmaceutical raw materials, intermediates, and final products that include these amorphous materials are widespread and varied (Table 1). 

This conciusion was confirmed " by an investigation of the rate of lactone formation of the phosphoribonic acid. (Levene and Simms had previously shown that if hydroxyls (4) and (5) are both free the formation of both the y- and the 5-lactone can be detected if position (4) is substituted and (5) is free, the 5-lactone is formed at a relatively rapid rate if position (5) is substituted and (4) is free, the y-lactone is slowly formed.) The transformation of the phosphoribonic acid to its lactone in aqueous solution was found to proceed smoothly and very slowly, a property of sugar acids so substituted that they can only give rise to 7-lactones. The formation of 5-lactone was not observed, as was to be expected if position (5) of the sugar is substituted. 

Lactones are in principle reducible to hydroxyaldehydes, and when applied to lactones of sugar acids the method works well because cyclic acetal or ketal formation stabilizes the carbonyl function and prevents overreduction [3,96-100]. In particular, d-ribose may be prepared from the cathodic reduction of D-ribono-y-lactone as in Eq. (24) the optimum conditions for this reaction include careful buffering of the electrolyte [97-100]. 

BMB has been used to reduce 2,3,5,6-tetra-O-acyl-D-hexono-y-lactones to the furanoses in high yields. Furanose derivatives are difficult to obtain by other methods, but the new method takes advantage of the preferential conversion of sugar acids into y-lactones. 

Vegetable notes are based on a balance of sugar, acids and salt. 

The Kolbe electrolysis of sugar acids to give radicals and their subsequent trapping with a radical source gave the chain-extended C-glycoside 27 as the major product (Scheme 7). Compounds such as 27 are useful as stable nonionic tensides and are expected to show liquid crystalline properties [11]. 

For example, at pH 8.3, /J,/J-ANDPBA selects D-tartailc acid over D-sorbitol in the ratio 7.2 1. Upon lowering the pH to 5.6, the selectivity becomes irrefutable at a ratio 11,000 1. The pH dependency of these probes offers the potential for switchable sensing of sugar acids in complex mixtures. 

Further research has shown that oxidative fission accompanies hy-droxylation, and that the yields of sugar acid, together with an equivalent amount of formic acid, depend on the parent glycal. Production of acid... 

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