Chitaric acid

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 ... 

Amino-u-gluconic acid--->Chitaric acid--- Epi-isosaccharic acid. 

Walden inversion on C2 has occurred in one of these sequences if in the first, then chitose, chitonic acid and isosaccharic acid have the configuration of D-mannose if in the second, i. e., in the deamination of 2-amino-D-gluconic acid, then chitaric acid and epi-isosaccharic acid are... 

Further work by V an Ekenstein and Blanksma7 led to a revision of the formulation of hydroxymethylfurfural. It was found that chitose on dehydration gave hydroxymethylfurfural which when oxidized was converted into hydroxymethylpyromucic acid, identical with the compound obtained by Fischer and Andreae from chitonic and chitaric acids.8 The nature of chitose (a 2,5-anhydrohexose) was such that Kiermayer s original formulation of /J-hydroxy-S-methyl-furfural could not obtain and the accepted formulation, -hydroxymethylfurfural (5-hydroxymethyl-2-furaldehyde (IV)) was assigned to the compound. 

When the above order of operations is reversed, i.e., when the oxidation precedes the treatment with nitrous acid, chitaric acid is formed. This anhy-droaldonic acid is isomeric with chitonic acid. (For additional details, see Chapter VII). 

A soln. of 3-desoxy-D-chitaric acid dimethylamide 6-monotosylate in ahs. tetra-hydrofuran added at —15 to a soln. of LiAlH4 in ahs. ether, heated rapidly to boiling at 45-46 with vibration, and refluxed 15 min. (-f-)-normuscarin. Y 65-70%.—A longer reaction time lowers the yield. F. amide reduction s. E. Hardegger, H. Furter, and J. Kiss, Helv. 41, 2401 (1958). 

Chiral methyl group, D2 Chitaric acid, Y20 Chitosenine, K4 ... 

Dihydroxyadipic acid, A3.3 Chitaric acid, Y20.7 Dimethyl tartrate, A2.6... 

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