D-Galactonic acid

The cyclization of pentaacetyl-o-gluconic thioamide with chloroacetone and of pentaacetyl-D-galactonic acid thioamide with phenacyl bromide give the corresponding 4-substituted 2-(D-galactopentaacetoxypentyl)-thiazoles (27) (660) but in low yield (23 to 27%) (Scheme 13). The products may be deacetylated in the usual way. These compounds are interesting from a pharmacological point of view. 

Lacton-bindung, /, lactonic linkage, -saure, /. lactonic acid, lactone acid (a compoimd which is both an acid and a lactone) lactonic acid, D-galactonic acid. 

The 2-keto acids such as 2-keto-D-galactonic acid (XXIV) can be derived from the corresponding osone (XXIII) by oxidation with bromine.10 Oxidation of L-gulosone by the same method has provided 2-keto-L-gulonic acid. The success of this oxidation depends to a large extent upon the purity of the osone subjected to oxidation and this, as previously stated, is controlled by the purity of the osazone. 

Fleet reported the synthesis of a new class of carbopeptoid-cyclodextrin, cyclo[(6-amino-6-deoxy-D-galactonic acid)4] with a 28-membered ring in which... 

The fermentative oxidation of D-galactose or D-galactonic acid to D-iyxo-2-hexulosonic acid by Aerobacter aerogenes,6 9 Pseudomonas... 

O. F. Hedemberg, On the esters, as well as the monomolecular /i- and y-lactones, of D-mannonic and D-gluconic acids on ortho-bis-D-galactonic acid, D-galactonic-y-lactone and its mono-hydrate, J. Am. Chem. Soc., 37 (1915) 345-372. 

Application of the same two-reaction sequence to disaccharide B will provide D-glucose and D-galactonic acid. Each disaccharide provides a different pair of products. This clearly distinguishes one disaccharide from the other. 

Karrer and Meyer25 showed that the rotatory dispersion curve of the copper salts of glucosaminic and chondrosaminic acids bore a close resemblance to those of the D-amino acids but differed considerably from those of the L-amino acids. Replacement of the amino group by a hydroxyl residue did not produce any change since both D-gluconic and D-galactonic acids resemble the D-amino acids in their rotatory dispersion.23... 

The condensation of fatty acids with o-phenylenediamine has been carried out effectively by refluxing the components in 4 N hydrochloric acid.19 Moore and Link, in their second paper on the preparation of benzimidazoles,20 stated that this procedure gave less satisfactory yields with the aldonic acids, the yield from D-galactonic acid being only 24%. 

Many functional derivatives incorporating a thiazole ring in their structure have been produced by this method. An illustrative example is the condensation of pentaacetyl-D-galactonic acid thioamide with chloroacetone to give 4-methyl-2-(D-galactopen-taacetoxypentyl)thiazole which is deacetylated in the usual way (Scheme 164) (69ACH(62)179). 

Reduces Tollens reagent to give D-galactonic acid and D-talonic acid. 

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