Aldose aldaric acids from

Bromine (hypobromite) and hypoiodite oxidations are particularly useful for the preparation of aldonic acids from aldoses and of aldaric acids from glycuronic acids. Primary alcohol groups also undergo oxidation by these reagents, although this conversion is of less value glycosides can thus be converted into glycosiduronic acids, and alditols into aldoses and aldonic acids. 

Aldaric acid (Section 25.6) The dicarboxylic acid resulting from oxidation of an aldose. 

Thedicarboxylic acids formed from aldoses by replacement of both terminal groups (CHO and CH2OH) by carboxy groups are called aldaric acids (see 2-Carb-23). 

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. 

Aldonic and aldaric acids are usually obtained by oxidation methods from the corresponding aldoses, whereas a glycoside is the usual starting material for the synthesis of glycuronic acids, important natural sugars that are constituents of many polysaccharides. 

Aldaric acids may be prepared from aldoses or aldonic acids by oxidation in aqueous solution with oxygen over platinum-charcoal255 or platinum-on-alumina.256 The effect of such promoters as bismuth or gold has also been studied.257 Hydrogen peroxide in the presence of iron salts has been used for the oxidation of uronic acids to aldaric acids.258... 

When aldoses are oxidised with nitric acid, saccharic acids are formed. Both aldehyde and primary alcohol groups are oxidised to carboxyl groups. Glucose on oxidation with nitric acid produces glucaric or glucosaccharic acid. The aldaric acid produced from galactose is called as mucic acid. 

As depicted in Scheme 21.1 for the oxidation of glucose, three general types of acids can be produced by the oxidation of a sugar aldonic acids in which only the aldehyde of the parent aldose has been oxidized to the acid aldaric acids that are dicarboxylic acids with one carboxy group coming from the oxidation of the aldehyde and the other from the primary alcohol at the other end of the carbon chain or uronic acids derived from the selective oxidation of the primary alcohol without the oxidation of the aldehyde. 

Scheme 1-6 The family tree of aldoses derived from (+)-glyceraldehyde. The Fischer projections of the corresponding aldaric acids are, variously, chiral and asymmetrical (Ci), chiral and symmetrical (C2), or achiral and symmetrical (Cs).

Carbohydrate diacids (aldaric acids) are derived from oxidation of the terminal carbons of simple aldoses. Several aldaric acids are suggested as being reasonable candidates for commercial development, based on potential applications, and availability and cost of the individual simple sugar precursors. 

The term carbohydrate diacids as used in this report represents that class of compoimds know as aldaric acids, i.e., simple diacids derived from oxidation of the terminal carbons of aldoses. As a class of compounds aldaric acids have been known for more than a century and some of these diacids played an important role in Emil Fischer s assignment of the relative configurations of naturally occurring D-aldoses (1). Surprisingly, these molecules have seen very little chemical application over the past century but their time may have arrived to be considered as valuable and versatile synthons for preparation of specialty chemicals and polyamides. The material in this report presents an overview of... 

Aldaric acid (Section 22.6C) An a,a)-dicarboxylic acid that results from oxidation of the aldehyde group and the terminal 1° alcohol group of an aldose. 

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