Hydrolysis of the GlcNAc oxazoline: deamidation and acyl rearrangement.
The specific deamidation of 2-acetamido-1,3,4,6-tetra-O-acetyl-alpha-D-glucopyranose is achieved by p-toluenesulfonic acid-promoted hydrolysis of 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-alpha-D-glucopyrano)-[2,1 -d]-2- oxazoline 2 to give quantitative formation of the 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-alpha-D-glucopyranose p-toluenesulfonate (5d). This two-step procedure provides an amino sugar which may be readily acylated to give novel glycoconjugates. Alternatively, base-catalyzed O-1-->N-2 acyl rearrangement of the amino tosylate 5d gives the 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-D-glucopyranose 4 as a 9:1 mixture of alpha and beta anomers. Thus, hydrolysis of GlcNAc oxazoline 2 gives the amino-ester 5 as the kinetic product and the amido-alcohol 4 as the thermodynamic product.
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Department of Chemistry and Biochemistry, University of Maryland, College Park 20742, USA.
Davis
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D000215:Acylation; D002240:Carbohydrate Sequence; D005947:Glucose / Q000031:analogs & derivatives* / Q000737:chemistry; D006001:Glycoconjugates / Q000737:chemistry*; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry*
C097669:2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxyglucopyrano)(2,1-d)-2-oxazoline; D006001:Glycoconjugates; D010080:Oxazoles; D005947:Glucose