General Chemistry of the 2-Amino Sugars

The Free Amino Sugars and Their Acetyl Derivatives 

The isomeric pentacetates of glucosamine were prepared as long ago as 1899 by Lobry de Bruyn and van Ekenstein85 and the proportions of the o-and /3-isomers obtained with various reagents are shown below in Table II. 

These reagents have also been applied to chondrosamine with similar results thus reagent (1) gave predominantly the a-pentacetate and reagent (3) mainly the /3-form although under certain conditions it could effect a 0 — a-transformation.,M  

Selective acetylation of the basic group in amino sugars can be achieved if silver acetate and acetic anhydride in methanol are used as the acetylating reagents. The products are the characteristically crystalline N-acetates. 

Although the existence of furanose and open chain forms of amino sugars in natural products has not so far been reported, such derivatives have been prepared synthetically as reference compounds.M,Tl Glucosa- 

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