Sugar Acids and Lactones

Studies on the kinetics of oxidation of free sugars by various oxidants are referred to in Chapter 2. 

1 Aldonic Acids, Aldaric Acids, and Their Amides, Lactones and Lactams 

3- Di-0-galloyl-4-0-( )-caffeoyl-L-threonic acid and 2-0-galloyl-4-0-( )-caffeoyl-L-threonic acid have been isolated from the leaves of Cornus con-trover sa  

Reagents i, TbdmsCI ii, MBS, HgO iii, Jones oxid iv, NaBH4, CeCIa 

Both diastereomeric N-acetylneuraminic acid-derived nononic acids 12a and 

Carbohydrate Chemistry, Volume 34 The Royal Society of Chemistry, 2003 

H And C n.m.r. methods have been used to determine the preferred conformations of the four D-pentono-1,A lactones and D-glucono-, D-mannono-, D-gulono- and D-galactono-1, -lactone. The kinetics of hydrolysis of D-glucono-l, 4-lactone have been examined in detail, and calcium D-arabinonate has been shown to epimerize to a mixture containing 8o of the D-ribo-lsomer at 137°C in the presence of calcium hydroxide. 

References to the use of sugar aldehydes in chain-extending syntheses of unsaturated acids are given in Chapter 12. 2,3-0- 

One Chinese report has described a commercial process for the production of D-glucono-6-lactone from calcium gluconate, and another 

D-Erythrorbic acid has been oxidized, cyclized and acetonated to give the D-erythronolactone acetal (1),  

Several unsaturated aldonlc acid derivatives have been reported. The enantiomeric 2,3-dideoxy analogues (7) of ascorbic acid have been prepared from 5,6-0 -isopropylidene-L-gulono- and D-mannono-1, -lactones by formation of their 2-(dimethylamino)-l,3-dioxolane 

Several reactions of aldonic acids have been reported. Aldono- 

The main product of reaction between D-ribono-y-lactone and benzaldehyde dimethylacetal is the 2,3-acetal and not the 2, -acetal of the 6-lactone as previously proposed.Long chain aliphatic amines (Cg-C g) have been condensed with D-gluconic acid lactone to give amphlpathic products which form gels at low concentrations in aqueous solution. The morphology of the gels has been Investigated by electron microscopy. 

The lactone moiety 6 found in mevinic acids has been synthesized from L-malic acid using a chiral sulfoxide reagent to control the stereochemistry at C-3. Synthesis of the negamycin lactone 7 has been reported, while a lactone precursor of L-acosamine and L-daunosamine is discussed in Chapter 9. 

The isomeric 2-deoxy-1,4-lactones 8 and 9 have been synthesized in a multi-step procedure from levoglucosenone, while the branched lactones 10 and 11 have been prepared by radical addition [C6H13I or Ph(CH2)3l, Bu3SnH, AIBN] to an unsaturated aldonic acid ester.The lactone 12, an intermediate in the synthesis of pseurotin A, has been prepared from D-glyceraldehyde in a multi-step procedure. Thermally-induced cleavage of nitrate ester 13 [derived from 

A route to l,5-dideoxy-l,5-imino-D-xylonolactam has utilized a 5-azido-5-deoxy-aldehydo-T -xylose derivative,and a route to C-glycosides by reaction of aldonolactone derivatives with alkyl lithiums followed by triethylsilane reduction is elaborated in Chapter 3. 

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Oxidation to Sugar Acids and Lactones. When the aldehyde group of an aldose is oxidized, the resulting compound is an aldonic acid (salt form = aldonate) (11)4. Some aldonic acids are products of carbohydrate metaboHsm. 

Tables V-LVII detail H and F shift and coupling information, and Tables LVIII to LXXI incorporate the C-n.m.r. data. The data within this compilation are arranged according to the following outline hexoses prior to pentoses, followed by anhydro sugars, sugar acids and lactones, amino sugars (and their synthetic, A -containing precursors), mono-, di-, and tri-deoxy sugars, branched derivatives, ketoses, polyfluorinated monosaccharides, and, finally, difluorinated amino sugars. Within this compilation, and even within each table, pyranoid derivatives are listed prior to their furanoid counterparts, hexoses prior to pentoses, functionalized prior to deoxy compounds the arrangement within each sub-table is made alphabetically.

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