2 Acetamido 3,4,6-tri 0 acetyl

Since then, this method has been extensively applied to, for example, the synthesis of 3-0-(2-acetamido-3,4,6-tri-0-acetyl-2-deoxy-/ -D-glu-... 

Similarly, Shen and coworkers36 obtained 4-0-(2-acetamido-3,4,6-tri-O- acetyl - 2 - deoxy -/ - d- glucopyranosyl) -N- (benzyloxycarbonyl)homo-serinamide (164) by coupling 2-acetamido-3,4,6-tri-0-acetyl-2-deoxy-a-D-glucopyranosyl chloride (6) with 2-N-(benzyloxycarbonylamino)-4-hydroxybutanamide128 (163) in the presence of mercury dicyanide. 

The product is scraped from the walls of the flask and broken up by means of a curved spatula. The solid is collected on a 12.5-cm. Buchner funnel, washed with two 150-ml. portions of dry ether, dried by suction on the filter for 5 minutes, and stored in a desiccator over sodium hydroxide and phosphorus pentoxide. Analytically pure 2-acetamido-3,4,6-tri-0-acetyl-2-deoxy-a-D-glucopyranosyl chloride is obtained weight 55-65 g. (67-79%) m.p. 127-128° (Fisher-Johns apparatus) (Note 7) typical — NHCOCH3 absorptions at 6.09 n and 6.49 n in the infrared. Evaporation of the mother liquors and addition of ether to the concentrated solution gives an additional 4-6 g. (5-7%) of crystalline product, m.p. 125-127°, that is sufficiently pure for most purposes. The pure product may be stored in an open dish in a desiccator at room temperature for at least 3 years without decomposition (Note 8). 

The direct one-step preparation of 2-acetamido-3,4,6-tri-0-acetyl-2 -deoxy-a-D-glu copyranosyl chloride was reported by Micheel and co-workers,3 and the described procedure is essentially the method of Horton and Wolfrom.4 The product was first prepared through a two-step route from 2-amino-2-deoxy-D-glucose hydrochloride by Baker and co-workers,5 and a number of adaptations of this method have been described6-8... 

In order to have a milder cleavage of the chiral auxiliary, various other glycosyl-amines have been introduced, such as 2-acetamido-3,4,6-tri-0-acetyl-l-amino-2-deoxy-/i-D-glucopyranose 30 [38], 2,3,4,6-tetra-0-alkyl-/i-D-glucopyranosylamines 31 [39] and l-amino-5-desoxy-5-thio-2,3,4-tri-0-isobutanoyl-/ -D-xylopyranose 32 [40] (Scheme 1.14). 

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