Oxidation of arabinose

Oxidation of (—) arabinose with warm nitnc acid gave an optically active aldanc acid... 

M. K. Singh, N. Prasad, and H. K. Sinha, Kinetics of oxidation of galactose and mannose with iodine in alkaline media, Asian J. Chem., 6 (1994) 636-640 (Chem. Abstr., 121 (1994) 179998y) M. K. Singh, N. Prasad, H. K. Sinha, and V. P. Singh, Kinetics and mechanisms of oxidation of arabinose and xylose by iodine in alkaline solutions, J. Indian Chem. Soc., 70 (1993) 74-75 (Chem. Abstr., 120 (1994) 107576) and references therein. 

The operon is then transcribed, and the proteins required for oxidation of arabinose are produced. 

Oxidation of (-)-arabinose with warm nitric acid gave an optically active aldaric acid. Because the hydroxyl group at C-4 of ( )-arabinose is at the right in a Fischer projection formula (evidence of step 1), the hydroxyl at C-2 must be to the left in order for the aldaric acid to be optically active. 

Oxidation of (-)-arabinose with warm nitric acid gave... 

The selective oxidation of arabinose to arabinonic acid by molecular oxygen has been carried out at 60°C in water on monometallic and bimetallic Pd-Au catalysts supported on nanosized ceria. Arabinose is extracted from a hemicellulose called arabi-nogalactan found in larch species, with galactose and D-glucuronic... 

The oxidation of aldoses and sugar phosphates by Cr(VI) has been reviewed (23 refs.). The kinetic behaviour and the relative reactivities of several trioses, tetioses, pentoses and hexoses, amino sugars, and methylated sugars towards potassium permanganate in perchloric acid solution have been examined. Mechanisms have been proposed for the oxidation of arabinose and xylose by iodine in alkaline solution and by alkaline NBS under Ru(Vni)-catalysis. For the oxidation of monosaccharides by sodium iV-bromobenzenesulfonamide in alkaline media, reaction via 1,2-enediol intermediates has been postulated. 1 1 Stoichiometry has been observed in the oxidation of D-fructose with PCC. ... 

On oxidation of the phenylosotriazole derivative of the disaccharide with sodium periodate, three moles of periodate are consumed with the formation of one mole each of formic acid and formaldehyde per mole of the phenylosotriazole derivative. If the D-glucose in the u-glucopyrano-syl-L-arabinose phenylosotriazole were attached to carbon atom 4 of the L-arabinose derivative, oxidation of this compound with sodium periodate would require two moles of periodate and would liberate one mole of... 

The rate of oxidation of other monosaccharides (e.g. galactose, mannose, xylose, arabinose and fructose) by glucose oxidase has been shown to be negligible or zero but some derivatives of glucose do react slightly, e.g. 2-deoxy-D-glucose shows a reaction rate of less than 5% of that with /3-D-glucose. 

The transformation of L-arabinose (58) to lactone 57 was based on a route developed by Marquez and Sharma [51] Selective protection of the primary hydroxy group with TBDPSCl and oxidation of the lactol moiety with bromine afforded lactone 59. Subsequent selective deoxygenation a to the carbonyl group proceeded under Barton-McCombie conditions providing lactone 57 in 21% yield (Scheme 14). 

The condensation of 2,4,5-triamino-6-hydroxypyrimidine and 5-deoxy-L-arabinose phenylhydrazone 1042, followed by oxidation of the intermediate 1043, gave biopterin 1044. The tetrahydrobiopterin is the natural cofactor of phenylalanine hydrolase. Various stereochemical isomers were also pre-... 

O-Isopropylidene-D-erythrose ( ) (15), obtained either by acetonation of D-erythrose ( ) or by periodate oxidation of 3,4-0-isopropylidene-fi-arabinose (1, ]J), reacted with ethoxycarbonylmethy-lenetriphenylphosphorane in refluxing benzene (18) to give the E-alkene ( ) as the major product (56%) together with the Z -alkene ( ) (21%), As expected (1 -M) the alkenes (14) and (f5) readily cyclized to tetrahydrofurans (16) under very mild basic conditions. Initially the 6 anomer of (16) was favored C86% from (lA) and 100% from ( )] at equilibrium the a anomer preponderated (82%) (19). 

Electrochemical detection of carbohydrates at nickel-copper and nickel-chromium-iron alloy electrodes has been reported for sorbitol, and has been used as a detector for HPLC analysis [36]. Oxidation of various carbohydrates at the electrodes was used for detection, and baseline separation was achieved for mixtures of sorbitol, rhamnose, glucose, arabinose, and lactose. 

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