Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Arabinonic acid

The selectivity was enhanced by adding small amounts of anthraquinone-2-sulfonate (A2S), which decreased the formation of deoxy by-products. Thus, by adding 260 ppm of A2S with respect to arabinonic acid the selectivity to deoxy-products decreased from 4.2 to 1.6%. A2S acted as a permanent surface modifier since the catalyst was recycled with the same selectivity without further addition of A2S. The highest selectivity to arabitol was 98.9% at 98% conversion, with a reaction rate of 73 mmol h 1 gRU 1 at 80 °C. [Pg.60]

Lichtenthaler, F. W. Klimesch, R. Muller, V. Kunz, M. Disaccharide-building blocks from isomaltulose glucosyl-a(l—>5)-D-arabinonic acid and ensuing products, Liebigs Ann., 1993, 975-980. [Pg.62]

Treatment of D-fructose or 1-O-substituted D-fructose with calcium hydroxide produced only the Q -D-glucosaccharinic acid (2-C-methyl-D-ri-bonic acid) and no jS-D-glucosaccharinic acid (2-C-methyl-D-arabinonic acid). However, when D-fructose was treated with sodium hydroxide, the D-glucosaccharinic acids were not detected. In order to confirm this... [Pg.292]

The oxidation of some hexoses49 and pentoses50 by A-chloroarylsulfon-amides in alkaline conditions has been conducted, and the kinetics studied. The products were identified as the corresponding aldonic acids for aldoses, and arabinonic acid for fructose. Further studies51 indicated that both... [Pg.323]

The starting material in this synthesis was L-arabinonic acid y-lactone 33, which was readily derived from L-arabinose by tritylation and bromine oxidation (77, 75). Conversion of 33 to 34 was carried out by the similar procedures with the preparation of 17 and 21. [Pg.167]

Fig. 8-15. Possible carboxyl group structures formed in cellulose during chlorine and hypochlorite stages. 1, Arabinonic acid 2, erythronic acid 3, glucuronic acid 4, dicarboxylic acid. Fig. 8-15. Possible carboxyl group structures formed in cellulose during chlorine and hypochlorite stages. 1, Arabinonic acid 2, erythronic acid 3, glucuronic acid 4, dicarboxylic acid.
Fig. 8-18. Oxidative stabilization of cellulose through formation of aldonic acid end groups. R is cellulose chain. After oxidative formation of a glucosone intermediate this undergoes a benzilic acid rearrangement strongly favoring formation of mannonic acid end groups (2). In addition, cleavage of C-1 to C-2 and C-2 to C-3 bonds gives rise to the formation of arabinonic acid (3) and erythronic acid (4) end groups. (In this simplified scheme only the main products are shown.)... Fig. 8-18. Oxidative stabilization of cellulose through formation of aldonic acid end groups. R is cellulose chain. After oxidative formation of a glucosone intermediate this undergoes a benzilic acid rearrangement strongly favoring formation of mannonic acid end groups (2). In addition, cleavage of C-1 to C-2 and C-2 to C-3 bonds gives rise to the formation of arabinonic acid (3) and erythronic acid (4) end groups. (In this simplified scheme only the main products are shown.)...
There are three known metabolic pathways to 3-deoxyulosonic acids. In the first, aldonic acids, formed by oxidation of aldopyranoses to the corresponding lactones, are dehydrated to the ulosonic acids (see Fig. 6). Thus, D-arabinose is converted by way of D-arabinonic acid to 3-deoxy-o-ffZj/cero-pentulosonic acid. The latter is then subjected to oxidative cleavage, yielding pyruvic and glycolic acids. L-Arabinose is oxidized and dehydrated to the 3-deoxy-L-g Z2/cero-pentulosonic acid, which is further oxidized to... [Pg.253]

Aiabinofuranose, 3,6 -di - 0 - (methoxy-carbonyl)- ,-, 1,2-carbonate, 108 Arabinogalactan, 73, 74 fractional precipitation of, 55 purification of, 56 Arabinonic acid, D-, formation of 3-deoxy-D-oro5fno-heptu-losonic acid 7-phosphate from, 253 Arabinopyranoside, bis (methyl 3,4-0-isopropylidene - /3 - n -, 2,2 - carbonate, 118, 132 2,2 -thionooarbonate, 132, 133 —, methyl 3,4-0-isopropylidene-/J-n-, 118, 119... [Pg.418]

D-, 5-phosphate, conversion to octulo-sonic acid, 254 I/-, 1,2 3,4-dicarbonate, 108 L-, enzymic conversion to L-arabinonic acid, 253... [Pg.418]

In a final step, different mono- and disaccharide lactones (e.g. 5-gluconolactone, glucopyranosyl arabinonic acid lactone etc.) reacted with the synthesized ami-nopolysiloxanes. The reaction lasted 5-6 h, either in refluxing methanol or in ethanol or isopropanol at 70 °C. The reaction gave the expected sugar silicone derivatives quantitatively as yellow or white powders. [Pg.185]

If the two lowest asymmetric carbon atoms possess the D-erythro configuration, a -D-glucosaccharinic acid must be either 2-C-methyl-o-arabmo-pentonic acid or 2-C-methyl-D-ribo-pentonic acid. The initial choice between these two possibilities was made by Nef, who chose the D-arabino configuration because of similarities between certain alkaloid salts of the saccharinic acid and the corresponding salts of n-arabinonic acid. However, subsequent developments make the D-ribo configuration appear the more... [Pg.46]

Amyloses, 273, 283, 306, 310, 340, 341 Aniline, p-bromo-, 112 Anthranilic acid, 155 Arabinitol, 2-amino-2-deoxy-n-, 60 Arabinonic acid, 2,3,5-tri-O-methyl-D-, amide, 195... [Pg.362]

Weygand and Bergmann investigated the oxidation of certain derivatives (known as Amadori products) of l-amino-l-deoxy-n-fructose. The oxidation of 1-deoxy-l-p-toluidino-n-fructose in 2 V ammonium hydroxide at 50° in the presence of a platinum-on-carbon catalyst led to the degradation of the compound to n-arabinonic acid, presumably according to the following sequence. [Pg.200]

The oxidation of the enolized Amadori compound yields D-arabinonic acid and JV-fonnyl-p-toluidine. The latter is cleaved, and its formaldehyde residue, on further oxidation, gives carbon dioxide and formic acid. The oxidation of the 1-p-anisidino-l-deoxy- and 1-deoxy-l-p-phenetidino- derivatives of D-fructose jdelds D-arabinonic acid in the same way. [Pg.201]


See other pages where Arabinonic acid is mentioned: [Pg.111]    [Pg.60]    [Pg.52]    [Pg.224]    [Pg.11]    [Pg.33]    [Pg.400]    [Pg.83]    [Pg.83]    [Pg.35]    [Pg.202]    [Pg.206]    [Pg.235]    [Pg.329]    [Pg.16]    [Pg.218]    [Pg.1125]    [Pg.183]    [Pg.418]    [Pg.591]    [Pg.591]    [Pg.184]    [Pg.1098]    [Pg.54]    [Pg.181]    [Pg.9]   
See also in sourсe #XX -- [ Pg.59 ]

See also in sourсe #XX -- [ Pg.66 , Pg.189 ]

See also in sourсe #XX -- [ Pg.46 ]

See also in sourсe #XX -- [ Pg.181 , Pg.201 , Pg.202 ]

See also in sourсe #XX -- [ Pg.213 ]

See also in sourсe #XX -- [ Pg.76 ]




SEARCH



Arabinon

Arabinonic acid hydrogenation

Arabinonic acid lactone

Arabinonic acid, 2-deoxy

Arabinonic acid, formation

D-Arabinonic acid

© 2024 chempedia.info