Glucosamine acids

Let us now return to the pioneering work of Fischer and Tiemann.4 Chitonic acid is produced from D-glucosamine by deamination and oxidation, in that order. If the order is reversed, however, i. e., if D-glucos-amine is first oxidized to D-glucosaminic acid (2-amino-D-gIuconic acid) and the latter substance subsequently deaminated, chitonic acid is not the product. Instead an isomeric 2,5-anhydro hexonic acid (chitaric acid) is obtained. These facts may be summarized thus ... 

Further consideration needs to be given to the interesting fact that although D-glucosaminic acid (2-amino-D-gluconic acid) undergoes de-amination. with the establishment of a 2,5-anhydro ring, the deamination... 

Procedure Synthesis of Xylonic, Galactonic, Mannonic, 2-Deoxygluconic Acid and Synthesis of 2-Amino-2-deoxy-gluconic Acid (Glucosaminic Acid)... 

Pezzotti, F., Therisod, H. and Therisod, M., Enz3Tnatic synthesis of D-glucosaminic acid from D-glucosamine. Carbohydr. Res., 2005, 340, 139. 

Hope, D.B. and Kent, P.W., Ester and lactone linkages in acidic polysaccharides. Part II. Lactones of D-glucosaminic acid. J. Chem. Soc. Abstr., 1955, 1831. 

The free nitriles of iV-methyl-L-glucosaminic acid and iV-methyl-L-mannosaminic acid have been prepared by Wolfrom, Thompson and Hooper by the Kiliani-Fischer cyanohydrin synthesis. 

J. M. Merrick and S. Roseman, D-Glucosaminic acid dehydrase, Methods Enzymol., 9 (1966) 657-660. 

An unusual classification of hexonic acids described by Levene21 was based on the differences in optical rotation between the free acid and its sodium salt. For example, in the D-gluconic acid series the sodium salt has the more positive rotation whereas in the D-mannonic acid group the reverse is the case and the acid has the more positive rotation. In comparison with these results glucosaminic acid was found to have a rotation of —15° (and its sodium salt +1.3°) and therefore these derivatives were in conformity with the D-gluconic acid series. 

Crystalline benzimidazoles have been obtained from all aldonic acids so far tested with only one exception that is known to the writer. Lohmar and Link29 reported that the condensation of D-glucosaminic acid (= 2-amino-2-desoxy-D-gIuconic acid) with o-phenylenediamine under a variety of conditions failed to yield a crystalline product. The direct oxidative condensation of D-glucosamine hydrochloride with o-phenylenediamine in the presence of cupric acetate yielded only the known 2-(D-arofro-tetrahydroxybutyl)quinoxaline (III) and not the desired benzimidazole. 

It was pointed out that N-methyl-L-glucosaminic acid nitrile was only the second nitrile in the sugar series to be isolated in the cyanohydrin reaction and that extension of the general procedure by which it was prepared should result in the isolation of other members. The nitrile of N-methyl-L-glucosaminic acid showed the same unusual mutarotation as does that of the lower-melting form of D-gluconic acid nitrile. Wolfrom and Thompson have noted that N-methyl-L-glucosaminic acid nitrile hydrochloride was a much more stable compound than the free base. 

In the preparation of N-methyl-L-glucosaminic acid nitrile by treatment of an ethanol solution of N-methyl-L-arabinosylamine with hydrogen cyanide, it was to be expected that the epimeric N-methyl-L-man-nosaminic acid nitrile Avould also be formed. Wolfrom and Thompson" were able to isolate in crystalline condition the acetylated nitrile of N-methyl-L-mannosaminic acid from this reaction mixture. This compound was converted to crystalline N-methyl-L-mannosaminic acid. 

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