Fructose periodate oxidation

The ultraviolet absorption spectra of compounds II from D-glucose and XI from D-fructose show an absorption band at 250 m/j, in accordance with their furan character.9 The product of periodate oxidation (V) and the dimethyl ester of the derived dicarboxylic acid (III) absorb at 285 and 262 m/i, respectively. The anhydrides of the condensates, XXXIV, do not exhibit selective absorption in the ultraviolet region, but the product of their oxidation (XXXVI) with periodic acid shows8 a band at about 270 m/i. 

Finally, Hirst s later contributions to monosaccharide chemistry must not be overlooked. With E. G. V. and Elizabeth Percival, four different trimethyl, 3,4- and 4,5-dimethyl, and the 4-methyl ethers of D-fructose were synthesized from isopropylidene derivatives having well established structures. Certain methyl ethers of D-mannuronic acid and D-glucuronic acid were also prepared, and their periodate oxidation was compared with that of related ethers of D-galacturonic acid. With Elizabeth Percival, he also contributed articles on the methyl ethers of mono- and di-saccharides, and on glycofuranosides from cyclic carbonates, to Methods in Carbohydrate Chemistry, Vol. 2 (1963). 

A similar analytical scheme for following the transformation of 3,4,6-tri-O-methyl-D-fructose gave somewhat better results. In these experiments, the disappearance of 3,4,6-tri-O-methyl-n-fructose was determined by measuring the formaldehyde released on periodate oxidation. The periodate consumption by these mixtures served as a check on the formation of products other than 3,4,6-tri-0-methyl-n-glucose and 3,4,6-tri-O-methyl-D-mannose, since each of the 3,4,6-tri-O-methylhexoses consumes 1 mole of periodate per mole. Actually, the periodate titers increased approximately 20% during the time-period that the apparent concentration of 3,4,6-tri-O-methyl-D-fructose diminished to about 60% of the initial concentration (when the reaction was carried out in sodium hydroxide solution). The change in periodate consumed was attributed to occurrence of demethylation. When the transformation was carried out in either calcium hydroxide or barium hydroxide solutions, the periodate consumption increased markedly. Hence, calcium and barium ions appear to catalyze this side reaction. ... 

The reaction of l-amino-l-deoxy-n-fructose with 2,4-pentanedione gives 3-acetyl-2-methyl-4-(D-araZ)mo-tetrahydroxybutyl)pyrrole (20). Acetylation of this compound yields a tetra-O-acetyl derivative, and periodate oxidation of (20) furnishes 4-acetyl-5-methylpyrrole-3-carboxaldehyde (24), which can be subsequently oxidized to 4-acetyl-5-methylpyrrole-3-carboxylic acid (26). 

Similar to dextran, insulin was activated via periodate oxidation and coupled with procainamide. The oxidation was performed at pH = 6 and 25 C and the rate of oxidation was measured by monitoring the periodate concentration with time. In contrast with earlier reports of Painter, who briefly described the periodate oxidation of insulin as a simple second order reaction, we observed significant deviation from mixed second order kinetics as evidenced in figure 6. This can be attributed to hemiacetal formation between the aldehyde groups of oxidized units and hydroxyl groups on adjacent fructose units ... 

These nearest neighbor interactions reduce the number of free fructose units accessible for periodate attack. Similar inter-residue hemiacetal formation has been reported for the periodate oxidation of other polysaccharides ... 

Thus, the carbon dioxide from the periodate oxidation of fructose is derived from C-2. The primary alcohols of C-1 and C-6 yield formaldehyde. All the secondary alcohols yield formic acid. The number of equivalents of periodate consumed indicates the number of carbon atoms in the monosaccharide that can be oxidized. The following functional groups are identified by the oxidation products ... 

Periodate oxidation is also valuable for structural studies of nonreducing disaccharides. A nonreducing disaccharide consisting of glucopyranose and fructofuranose should consume three moles of periodate and form one mole of formic acid. If the D-fructose residue were to exist in the disaccharide as the pyranoid form, it would consume four moles of periodate and form two moles of formic acid per mole of disaccharide. Consumption of three moles of periodate and formation of one mole of formic acid by actual oxidation of sucrose confirmed the furanose structure of the D-fructose residue in sucrose. ... 

Stable oxo-Cr(V) complexes were found to be formed with D-galactose (12) and D-fructose ligands, with EPR signals detectable even after 1 month.31>50>70 it was therefore concluded that periods of weeks are necessary to convert the Cr(VI) to Cr(III) complexes having saccharides as ligands, and this poses many environmental implications. In the studies of Cr(VI) oxidation of sugars conducted by Sala et al., the existence of intermediate Cr(V) complexes has indeed been firmly established.71... 

A typical chemical system is the oxidative decarboxylation of malonic acid catalyzed by cerium ions and bromine, the so-called Zhabotinsky reaction this reaction in a given domain leads to the evolution of sustained oscillations and chemical waves. Furthermore, these states have been observed in a number of enzyme systems. The simplest case is the reaction catalyzed by the enzyme peroxidase. The reaction kinetics display either steady states, bistability, or oscillations. A more complex system is the ubiquitous process of glycolysis catalyzed by a sequence of coordinated enzyme reactions. In a given domain the process readily exhibits continuous oscillations of chemical concentrations and fluxes, which can be recorded by spectroscopic and electrometric techniques. The source of the periodicity is the enzyme phosphofructokinase, which catalyzes the phosphorylation of fructose-6-phosphate by ATP, resulting in the formation of fructose-1,6 biphosphate and ADP. The overall activity of the octameric enzyme is described by an allosteric model with fructose-6-phosphate, ATP, and AMP as controlling ligands. 

On oxidation of 1 mole of planteose by periodic acid, 4.6 moles of oxidant were consumed, with the formation of 1.8 moles of formic acid (no formaldehyde was produced). After treating the oxidized product with an excess of sodium borohydride, the Seliwanoff test for fructose was negative, though a similarly oxidized and reduced sample of melezi-tose gave a positive fructose test. 

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