Aldonic acids characterization

Aldonic acids, characterization of, 373 —, 2-amino-2-deoxy-, deamination of, 191 —, 2,5-anhydro-, properties of, 220-229 Aldonolactones, 2-amino-2-deoxy-, deamination of, 189... 

The fourth student in this group, Stanford Moore, began his doctoral thesis research with Link in 1935. His work involved the development of a new, and still useful, procedure for oxidizing aldoses to the aldonic acids by potassium hypoiodite in methanol solution the resulting aldonic acids were then converted into nicely crystalline benzimidazole derivatives that proved more suitable for the characterization of carbohydrates than the classical osazones. This method, developed by Moore and Link (1940), was extended to the characterization of hexuronic acids, as their bis(benzimidazole)s, after oxidation to the glycaric acid (R. Lohmar, Dimler, Moore, and Link, 1942), of lactic acid (Moore, Dimler, and Link, 1941 Dimler and Link, 1942), and of ribose, fucose, and digitoxose (Dimler and Link, 1943). During these... 

The melting points of the various benzimidazoles (see Table I) cover a considerable range of temperatures, and with the specific rotations as observed in N hydrochloric acid or 5 % aqueous citric acid (see Table I) will serve to characterize new and identify known benzimidazoles from aldonic acids. While the substances usually melt with decomposition, the values are readily reproducible. The rotations will be discussed further in the final section of this review. 

Another method of preparing keto aldonic acids, those of the 2-keto type, is by oxidation of the corresponding osone. Neuberg and Kitasato obtained 18 g. of calcium 2-keto-D-gluconate from 20 g. of the osone by the action of bromine at 20 . Similarly, 2-keto-n-galactonic and 2-keto-maltobionic acids were prepared by Kitasato. The substances were characterized generally as the brucine salts because of the amorphous nature of the calcium salts. 

Complexes of Cr111 with ascorbate, which are likely to form during the reactions of Crvl with this major intracellular reductant, have been studied (mainly by Cieslak-Golonka and co-workers),1062-1064 but no definitive structural information has been obtained to date. Partially characterized Crm complexes with monosaccharides or their oxidized derivatives (e.g., aldonic acid) have been isolated from the reactions with either Cr1111092 or CrVI.1093,1094... 

The trimethylsilyl derivatives of 4- and 5-hexulosonic acids also give the rearrangement ion at m/e 292. In addition, the 5-hexulosonic acid derivative is degraded by a similar rearrangement-process, to form the ion m/e 306 (see Scheme 34). Aldonic acids can also be characterized by g.l.c. -m.s. of the corresponding per (trimethylsilyl) ated aldonolac-... 

The branched-chain aldonic acid derivative (1) has been shown to be a component of avilamycin by isolation of the product (2) of mild methanolysis and acetylation the latter compound was structurally characterized by X-ray analysis. ... 

Xylobenzimidazole forms the 2,5-anhydro derivative when heated with zinc chloride 40), The benzimidazoles are useful for the characterization of the sugars and of the aldonic, saccharic, saccharinic, and uronic acids 39 39a),... 

The salts and lactones of the aldonic and saccharic acids react readily with phenylhydrazine to form the hydrazides 48) The low solubility and ease of crystallization of the hydrazides have led to their use for the characterization and isolation of the acids. Aniline reacts in a manner similar to phenylhydrazine. 

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