Monosaccharides derived products

By treatment of chitin with alkali the acetyl groups can be removed and a polyglucosamine formed. This compound, chitosan, appears to be broken down with nitrous acid even under mild conditions, the sole product being a monosaccharide derivative. 

The oxidative effects of silver(II) complexes of pyridine carboxylates have been studied for a variety of substrates. With ar-amino acids, a rapid reaction occurred at 70 °C in aqueous solution with bis(pyridyl-2-carboxylato)silver(II). 4 The product was the next lower homologous aldehyde and yields were generally greater than 80%. Other substrates included primary and secondary amines, alcohols, monosaccharide derivatives, alkenes, arylalkanes and arylalkanols.90 Only minor differences were detected in efficiencies when 2-, 3- or 4-mono-, or 2,3-di-carboxylates were used as the oxidant. 

IV. Oxidation Products from Monosaccharide Derivatives and Related Compounds. 108... 

This review will be limited to a discussion of the structures and reactions of the aldehydes obtained from oxidation of cyclic carbohydrate derivatives. Such products as that from the oxidation of 1,2-0-isopropylidene-D-glucofuranose, which is a monoaldehyde, will not be dealt with. A monosaccharide derivative will normally give rise to a dialdehyde, a disaccharide derivative to two dialdehyde units linked together (or a tetra-aldehyde), and a polysaccharide will give a dialdehyde polymer (a polyaldehyde). All of these classes of compounds will be discussed. 

To jdeld a dialdehyde on periodate oxidation, a monosaccharide derivative must be held in a ring form by suitable substituents. The oxidation products can be divided into two classes those which generally do not contain hydroxyl groups elsewhere in the molecule, and form hemialdals, for example (3), and those which can form internal hemiacetals with a hydroxyl group elsewhere in the molecule, for example (4) the latter class... 

No broad division into two classes of oxidation products, similar to that made for the monosaccharide derivatives can be made for these oxidation products. There are nearly always several hydroxyl groups in the oxidation products and, therefore, there are generally several possibilities for hemi-acetal formation. Many of the oxidation products were prepared in the course of structural work and, with the exception of oxysucrose, have received little study. 

The reaction of phenylhydrazine with oxysucrose was found to be similar to that described for oxidized monosaccharide derivatives above, as only two molecules of the base reacted with the four potential aldehyde groups the product was assigned structure (89). Mester found that this derivative forms an amorphous bis(diphenylformazan) with benzenediazonium chloride, and so he assigned structure (90) to it. Acetylation of the formazan gave an amorphous product, identical with the formazan prepared from... 

Condensation of syn- or anti-27 with hydrazine afforded new pyrazole derivatives 28 with a stereodefined and protected amino diol side chain [64]. The preparation of push-pull substituted unsaturated monosaccharide derivatives and their use in the synthesis of nucleoside analogs have been reviewed [65]. Thus, the 2-formyl pentose glycals were transformed to the corresponding acyclo-C-nucleosides 29 [66]. Similarly, the benzy-lated 2-formylglycals reacted with hydrazine derivatives to afford the substituted l,2,4-tri-0-benzyl-lC-(lH-pyrazol-4-yl)-D-tetritols the deprotection of which was achieved with Pd/H2 to yield the lC-( 1-methyl-lH-pyrazol-4-yl)-D-tetritols [67]. 3-0-Benzyl-6-deoxy-l,2-0-isopropylidene-o -D-xylo-hept-5-ulofuranurono-nitrile was reacted with f, N-dimethylformamide dimethyl-acetal in THF to furnish the (E)-3-0-benzyl-6-deoxy-6-dimethyl-aminometh-ylene-l,2-0-isopropylidene-Q -D-xylo-hept-5-ulofuranurono-nitrile as a major product, and on treatment with carbon disulfide and methyl iodide under basic conditions afforded 3-0-benzyl-6-deoxy-l,2-0-isopropylidene-6-[bis(methylsulfanyl)methylene]-a-D-xylo-hept-5-ulofuranurono-nitrile. Further reaction with hydrazines yielded the reversed pyrazole-C-nucleoside analogs [68]. 

The lower rim 1,3-distal D-gluconyl calix[4]arene derivative 175 having an amidic linker was smoothly formed by deacetylation of the product obtained from 1,3-aminoethoxy calix[4]arene preorganized in the cone conformation and 2,3,4,5,6- pentaacetyl-o-gluconyl chloride. Its NMR-monitored interaction with some monosaccharide derivatives revealed their 1 1 complexation (2000T1883). 

FAB and El spectra of some acenaphtho[l,2-e][l,2,4]triazines and acenaphtho[l,2,4]triazolo[4,3-Z>] and [3,4-c][l,2,4]triazines attached to acyclic monosaccharide derivatives have been reported. The reaction of iV-a-acetyl-L-lysinamide and glucose has been examined with the assistance of electrospray mass spectrometry (along with capillary zone electrophoresis), providing evidence for a number of products exhibiting different degrees of dehydration and oxidation and for species with two lysines per glucose (relevant to cross-linking of... 

Tin(II) triflate has been used to catalyse the condensation between tetra-O-acetyl-a-D-glucopyranosyl bromide and primary and secondary alcohol groups on other monosaccharide derivatives. The products had the 3-configuration exclusively but the yields were modest (30-65%). In a related study the influences of catalyst, solvent, and temperature on the reaction of 0-(tetra-O-benzyl-a-D-glucopyranosyDtrichloroacetimidate with primary and secondary sugar alcohols were examined. With boron trifluoride in dichloro-methane at -I8—good yields (e.g. 80 for a secondary alcohol) and anomeric ratios (a,3, ca. 1 4) were obtained. 

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