Glucose 1,2-anhydro

Fig. 1. Anhydro-glucose units with 1—4 beta linkages as in ceUulose.

Aliphatic fluorodenitration has also been applied to mononitro compounds, specifically to an a-nitroepoxide Thus, l,2-anhydro-3 4 5,6-di-O isopropyli dene-1-C-nitro D mannitol and labeled potassium bifluonde give 2-deoxy-2-fluo-ro-3,4 5,6-di-O-isopropylidene aldehydo D glucose [J03, 104] (equation 30)... 

Deoxy-D-jcylo hexose 6-(dihydrogen phosphate) (21) has also been synthesized (2) the reaction sequence makes use of 3-deoxy l 2,5 6-di-O-isopropylidene D-galactofuranose (16), a compound that can be easily prepared from D-glucose (2, 60). The mono-isopropylidene derivative (17) formed by partial hydrolysis of the di-ketal is converted into the 6-tosylate (18) by reaction with one molar equivalent of p-toluenesulfonyl chloride. From this the epoxide (19) is formed by reaction with sodium methoxide. Treatment of the anhydro sugar with an aqueous solution of disodium hydrogen phosphate (26) leads to the 6-phosphate (20)... 

The widespread occurrence of long-range couplings in both furanose and pyranose derivatives explains why so many of the P.M.R. spectra of carbohydrate derivatives are apparently poorly resolved, even when the resolution of the spectrometer is above reproach. For example, the Hi resonance of the 1,6-anhydro-D-glucose derivative (12) is coupled to all of the other six ring protons. A further example of the line-broadening effect follows a consideration of the spectrum of 5,6-dideoxy-5,6-epithio-l,2-0-isopropylidene-/ -L-idofuranose for which the half-height... 

The first synthesis, by method a, of amylostatin (XG) was reported by Kuzuhara and Sakairi. The synthon for the cyclohexene moiety was the benzylated allyl bromide 382, derived from D-glucose by the sequence 378 — 382 of the Perrier reaction. The coupling reaction of 382 using an excess of 4-amino-T,6 -anhydro-4,6-dideoxymaltose tetrabenzyl ether (383), and sodium iodide in DMF for 3 days produced a mixture of the epimeric monocarba-trisaccharide derivatives, separation of which gave the protected derivatives in 15% yield. 

Fourteen DFAs and some oligomers were identified in caramel obtained by thermal treatment of inufin. - Monosaccharides (glucose, fructose), dehydration products (1,6-anhydro-p-D-glucopyranose, 1,6-anhydro-p-D-glucofuranose), disaccharides (gentiobiose and isomaltose), and oligosaccharides were also found in glucose and sucrose caramel. ... 

More-specific methods are available for identifying and quantitating the typical, amino sugar component of heparin (and some heparan sulfate species), namely, 2-deoxy-2-sulfoamino-D-glucose. Most of these methods are based on conversion of these residues into 2,5-anhydro-D-mannose by deamination with nitrous acid (see Section VIII,2). The 2,5-anhydro-D-mannose residues may be determined either colorimetrically,52-54 or fluorimetrically.55... 

It is to be noticed that although the anhydro ring of levoglucosan is stable to alkali (Tanret s preparative method consisted in the heating of aromatic jS-D-glucosides with aqueous alkali), it readily undergoes scission in the presence of acid. An isomeric glucose anhydride prepared in 1912 by E. Fischer showed, however, very different properties. 

Anhydro-D-glucose resulted, as mentioned, from the hydrolytic removal of a halogen atom at C6. Similar hydrolytic scission of sugar esters of carboxylic acids takes place without dehydration and with the liberation of the normal sugar. Thus, saponification of 6-benzoyl- or... 

Some examples will illustrate the applicability of this generalization in so far as it concerns alkaline scission. 5,6-Anhydro-l,2-isopropylidene-D-glucofuranose with alcoholic sodium hydroxide gives a mixture of isopropylidene-D-glucose and isopropylidene-L-idose. The latter results from inversion on C5, the former presumably by inversion on the non-asymmetric C6.7 3,4-Anhydro-l,2-isopropylidene-D-psicose (or allu-lose17) (XX) when treated with sodium hydroxide yields a mixture of products among which 1,2-isopropylidene-D-fructose (XIX) was detected (in the representations inversions are denoted by circles above the arrows and the carbons inverted are noted below the arrows). With sodium methoxide, however, l,2-isopropylidene-4-methyl-D-sorbose (XXI) is the chief product and results from inversion on C4.1S... 

The inference is that the hydrofuranol ring of XL can never be directly formed by the saponification of a 3-tosyl ester of D-glucose, but only indirectly by the intermediate formation and scission of an anhydro ring of the ethylene oxide type. The sequence of reactions involved in the conversion of methyl 3-tosyl-jS-D-gIueoside into methyl 3,6-anhydro-n-glucoside is shown by XXXVI to XL. 

Another example of the formation of a 3,6-anhydro ring by the saponification of a 3-tosyl-D-glucose derivative is furnished by the work of Peat and Wiggins11 who were able to isolate derivatives of no less than three anhydro sugars, one of which was 3,6-anhydro-D-glucose, from the... 

The configuration of the penturonic acid LV was not however conclusively proved to be that of D-xylose and consequently this experiment is not determinative in regard to the configuration, as distinct from constitution, of 3,6-anhydro-D-glucose. 

Anhydro-trimethyl-D- Methyl 3,6-anhydro-/9-r>-glucose dimethyl acetal (R=Me) galactopyranoside... 

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