Glycosylamines preparation

Kallin, E., Lonn, H., Norberg, T., and Elofsson, M. (1989) Derivatization procedures for reducing oligosaccharides, Part 3 Preparation of oligosaccharide glycosylamines, and their conversion into oligosaccharide-acrylamide copolymers./. Carbohydr. Chem. 8, 597-611. 

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. ... 

However, the azide-based protocol often has problems with the formation of byproducts under both azide formation and subsequent reduction. 388 Therefore, mainly aminolysis is used. Glycosylamines are prepared from GlcNAc, GlcNAc2, Glc, maltotriose, mal-toheptaose, and di- and triantenneary complex glycans, isolated from asialofetuin by preparative hydrazinolysis. A modification of the method by Likhosherstov is also employed. 379 ... 

Although much work has been done in an attempt to elucidate the structure of iV-substituted glycosylamines, rigid proof of their structures has not yet been achieved.43 Spectroscopic evidence is inconclusive,69 whilst chemical methods are of limited value because equilibrium between open-chain, pyranose, and furanose forms is possible. However, all such derivatives as ethers and esters so far prepared directly from A-glycosylamines have been shown to be pyranoid, and periodate oxidation of some N-glycosylamines has confirmed this conclusion.70 71... 

The addition-compounds of sodium bisulfite (or potassium bisulfite) with numerous sugars have199a been prepared in a pure state and have been shown to react with aromatic amines under conditions similar to those under which the free sugars react. -Substituted glycosylamines are formed, but the reaction with amino acids was not reported. 

Chida has coupled glycosylamines with 6-chloropurines to prepare models of spicamycin and septacidin, two Streptomyces metabolites that show antitumor activity [202]. As shown in Eq. (33), 5 mol % catalyst was used, and the reaction temperature was high (140 °C). Nevertheless, good yields of the desired N-aryl glycosylamine were obtained when BINAP was used as the ligand, NaOtBu as the base, and either MPM or SEM as the N9 protective group. 

The literature on /3-D-glucosiduronic acids is particularly voluminous, and the subject has been extensively reviewed from several aspects. Section III, dealing with this class of compounds, is devoted more to a general overview of their preparation, characterization, and reactions than to individual members. On the other hand, the categories of 1-esters of glycuronic acids and of (glycosylamine)uronic acids, which appear not to have been treated previously as separate topics, receive relatively more attention. 

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