Disaccharides products from acylated

Table IV (see p. 132) shows the products and yields obtained from the ammonolysis of acylated disaccharides.

In Tables III and IV, the yields and properties of the products isolated from the reaction of ammonia with acylated mono- and disaccharides are listed. 

The net result of all these competitive reactions is a possible mixture of normal and /3-glycosides and a possible mixture of two diastereo-isomeric orthoesters. In the course of the Konigs-Knorr procedure, water is usually formed from the reaction between hydrogen halide and silver oxide. The water formed, or deliberately employed, may take the part of the solvent alcohol, thus giving rise to products such as acidic orthoesters and normal tetra- and heptaacetates (for a disaccharide) of the sugars, and these compounds are subject to further changes, such as acyl migration. 

Two fatty acyl amidases, amidases I and II, purified from Dictyostelium discoideum, act upon the disaccharide (3, R = R = H, n = 1), which has been isolated from the lipopolysaccharide of a heptose-less mutant of Escherichia coli K-12. Amidase I removes the 3-hydroxymyristoyl unit, which is esterified to the amino-group of the 2-amino-2-deoxy-D-glucosyl residue adjacent to the C-1 phosphate of the disaccharide. The product is then acted upon by amidase II, which removes the remaining 3-hydroxymyristoyI unit from the amino-group on the distal 2-amino-2-deoxy-D-glucosyl residue. 

AT-Acyl Derivatives. — O-Protected 2-deoxy-2-trichloroacetamido-D-glucopyranosyl trichloroacetimidates, e.g. 54, have been used in the synthesis of -linked disaccharides with some success (see Chapter 3). The products could be converted into the corresponding 2-acetamido-derivatives by radical dechlorination (BuaSnH, AIBN). The 2-trichIoromethyl-oxazoline derivative 55, formed from 3,4,6-tri-0-acetyl-2-deoxy-2-trichloroacetamido-D-glucosyI acetate (on reaction... 

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