D-Glycosylamine

Anhydro sugars react similarly with amines substituted anilines lead to N-aryl-/3-D-glycosylamine derivatives.221... 

The formation10 12 of N-acetyl-a-D-glucofuranosylamine (15) from 1,2,3,4,6-penta-O-acetyl-D-glucopyranose, and, by extension, of other N-acyl-D-glycosylamines, would start with the rapid elimination of the acetyl group on 0-1 to give 89. In this way, C-l is ready to combine with ammonia to give the intermediate 90 and, subsequently, the... 

A recent paper gives the results of a study of the formation of N-p-sulfophenyl-D-glycosylamines in 0.01 M atiueous solutions of different pH values. Reaction proceeds best using excess of sugars at pH 3 to 4, slowly at pH 7, and not at all in alkaline solutions. Ammonium chloride shows no catalytic effect under these conditions, but acids, particularly acetic acid, act favorably. 

The reverse anomeric effect has been invoked to explain the observed conformational behavior of other a-D-glycosylamine derivatives in the form of their salts. For example, 9-a-D-mannopyrano-syladenine hydrochloride (21) has been assigned the JC(d)... 

This mechanism was developed mainly on the basis of experiments with A-aryl D-glycosylamines and, served a purpose to explain (a) the catalytic effect of carboxylic acids (b) the absence of die Amadori rearrangement in neutral medium" or for A-aryl D-glucosylamines derived from weakly basic amines such as dinitroaniline or indole "" (c) enoUzation, rattier ttian a 2,1-hydride shift, as ttie rate-determining step." ... 

Stereoselective Strecker reactions with galactosylamine 1 can also be achieved with sodium cyanide and acetic acid in 2-propanol. The reactions, however, proceed slowly and with a lower stereoselectivity, giving diastereomeric ratios of the products between 3 1 and 7 1. The scope of the method can be extended to other glycosylamines, e.g., 2,3,4-tri-O-pivaloyl-a-D-arabinosyl-amine which allows the stereoselective synthesis of (A )-amino nitriles61,62. 

Synthesis of ds-fused OZT starting from 2-amino-2-deoxy-D-glucose and D-mannose hydrochlorides in conditions similar to those applied for glycosylamines was recently published (Scheme 6).36 In contrast with data previously reported for tram-fused thiocarbamate,32 the isomeric isothiocyanates were not detected. 

Figure 9.13 A glycosylamine. Adenosine is a nucleoside and is an example of a glycosylamine in which the nitrogen atom of the purine, adenine, is linked directly to carbon 1 of /3-D-ribofuranose.

The initiating reaction between aldoses and amines, or amino acids, appears to involve a reversible formation of an N-substituted aldosyl-amine (75) see Scheme 14. Without an acidic catalyst, hexoses form the aldosylamine condensation-product in 80-90% yield. An acidic catalyst raises the reaction rate and yet, too much acid rapidly promotes the formation of 1-amino-l-deoxy-2-ketoses. Amino acids act in an autocat-alytic manner, and the condensation proceeds even in the absence of additional acid. A considerable number of glycosylamines have been prepared by heating the saccharides and an amine in anhydrous ethanol in the presence of an acidic catalyst. N.m.r. spectroscopy has been used to show that primary amines condense with D-ribose to give D-ribopyrano-sylamines. ... 

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