Xylonic acid

Xyhtol also is obtained by sodium borohydride reduction of D-xylonic acid y-lactone (32) and from glucose by a series of transformations through diacetone glucose (46). 

R" = -H, 5-0-carbamoyl-2-amino-2-deoxy-L-xylonic acid or the 3-deoxy derivative... 

Tri-O-acetyl-D-xylono-1,4-lactone D-Xylonic acid, y-lactone, triacetate (10) (79580-60-2)... 

Aside from the multifaceted chemical conversions, there are sources to develop into industrially viable microbial conversions. 1,2,4-Butanetriol, for example, used as an intermediate chemical for alkyd resins and rocket fuels, is currently prepared commercially from malic acid by high-pressure hydrogenation or hydride reduction of its methyl ester. In a novel environmentally benign approach to this chemical, wood-derived D-xylose is microbially oxidized to D-xylonic acid, followed by a multistep conversion to the product effected by a biocatalyst specially engineered by inserting Pseudomonas putida plasmids into E. coli ... 

Removal of the acetyl and nitrile groups by acid hydrolysis was also achieved by Wohl, who isolated a pentosazone from the products from heating pentaacetyl-D-glucononitrile with 2 N hydrochloric acid. Fischer also isolated what is now known to have been a 5-desoxy-L-arabinosazone from the products obtained by treatment of tetraacetyl-L-rhamnononitrile with 5% hydrochloric acid. At the same time partial transformation of the nitrile into the aldonic acid takes place as shown by Maquenne, who obtained D-xylonic acid by treating tetraacetyl-D-xylononitrile with concentrated hydrochloric acid. 

Xylose hydrogenation gave xylitol as a main product (selectivity typically over 99 %) and arabinitol, xylulose and xylonic acid as by-products, in lactose hydrogenation, the main product was lactitol (selectivity typically between 97 and 99 %) and lactulitol, galactitol, sorbitol and lactobionic acid were obtained as by-products. 

Figure 2. A. Consecutive xylose hydrogenation batches over sponge nickel catalyst (XA=xylonic acid). B. Influence of lactobionic acid (LBA) on lactose hydrogenation rate.

Anhydro-L-xylose, characterized as the benzimidazole derivative formed from the corresponding 2,5-anhydro-L-xylonic acid and o-phenylenediamine, has likewise been prepared92 by the action of one molar equivalent of periodic acid on 1,4-anhydro-D-glucitol. 

Epimerization of the potassium salts of L-arabinonic, D-ribonic, D-lyxonic, and D-xylonic acids in aqueous alkali was monitored kinetically by gas-chromatographic analysis of the silylated samples. Mass-spectrometric measurements indicated53 that the reaction proceeded by complete proton exchange at C-2. 

Incubation of D-xylose with an aqueous solution of bovine lens protein gave both xylitol and xylonic acid. Studies of the reaction under a variety of conditions suggest that both the reduction and oxidation reactions are protein (possibly enzyme) catalyzed and appear to be unique to lens... 

E. Yinan Li and M. S. Feather, The conversion of D-xylose to xylitol and D-xylonic acid by a bovine lens preparation, J. Carbohydr. Chem., 13 (1994) 499-505. 

Xylonic acid Dispersant Buchert etal., 1986 Buchert et al., 1988 Chun eta/., 2006... 

Buchert, J., Viikari, L., Linko, M. and Markkanen, P. 1986. Production of Xylonic Acid by Pseudomonas Fragi. Biotechnol. Lett., 8, 541-546. 

Buchert, J., Puls, J. andPoutanen, K. 1988. Comparison of Pseudomonas Fragi and Gluconobac-ter Oxydans for Production of Xylonic Acid from Hemicellulose Hydrolyzates. Appl. Microbiol. Biotechnol., 28, 367-372. 

Chun, B.-W., Dair, B., Macuch, P.J., Wiebe, D., Porteneuve, C. and Jeknavorian, A. 2006. The Development of Cement and Concrete Additive Based on Xylonic Acid Derived via Bioconversion of Xylose.Appl. Biochem. Biotechnol., 131, 645-658. 

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