Glycosylamines, reaction with /3-dicarbonyl compounds

A re-investigation of the reaction showed, in accordance with VotoCek s hypothesis, that the compounds obtained have properties (for example, color reactions, ultraviolet and infrared spectra, hydrolysis when examined chromatographically) similar to those of the /3-(glycosylamino) a, 8-un-saturated esters or ketones prepared directly from glycosylamines and i3-dicarbonyl compounds. The derivatives from L-rhamnose and ammonia with ethyl acetoacetate and with 2,4-pentanedione are, indeed, identical... 

The first observation on the reactions of glycosylamines with 3-dicarbonyl compounds is due to Elson and Morgan, who found that D-glucosylamine and 2,4-pentanedione, when heated in slightly alkaline solution, give a positive Ehrlich pyrrole test. They considered that 3-acetyl-2-methyl-4-(D-ara6wo-tetrahydroxybutyl)pyrrole (20) was formed and was responsible for the color reaction. 

When the reactions of some glycosylamines with 8-dicarbonyl compounds are carried out under milder conditions (in methanol in the cold), compounds that may be intermediates in the formation of the (tetra-hydroxybutyl)pyrroles may be isolated. For instance, from the reaction of D-glucosylamines with ethyl acetoacetate, ethyl 3-(D-glucosylamino)croto-nate (98) is obtained. The evidence for structure (98) is as follows. The... 

The reactions of monosaccharides (including glycosylamines) with i8-dicarbonyl compounds are interesting from the biochemical point of view, because they involve three of the major components (carbohydrates, lipides, amino acids) of living matter and because some of them can take place under physiological conditions. Although the study of these reactions... 

Amino acids may be involved in biochemical reactions of this type, through their conversion into glycosylamines by reaction with the monosaccharides. The glycosylamines may react directly with the /3-dicarbonyl compound, or after its Amadori rearrangement to the amino sugar. 

---