6-O-Benzyl- and 6-O-silyl-N-acetyl-2-amino-2-N,3-O-carbonyl-2-deoxyglucosides: effective glycosyl acceptors in the glucosamine 4-OH Series. effect of anomeric stereochemistry on the removal of the oxazolidinone group.
[reaction: see text] The 4-OH groups of both alpha- and beta-methyl glycosides of N-acetylglucosamine, protected with an oxazolidinone spanning the nitrogen and O-3, and bearing benzyl or silyl protection on O-6, show excellent reactivity as acceptors in couplings to a range of glycosyl donors. The enhanced reactivity of these acceptors is attributed in part to the tied back nature of the oxazolidinone, which reduces hindrance around the nucleophilic oxygen. The N-acetyloxazolidinone function also reduces the tendency seen in simple N-acetylglucosamines toward amide glycosylation, and removes the possibility of problematic hydrogen bonding networks. In the beta-, but not the alpha-, series selective hydrolysis of the N-acetyloxazolidinone directly to the N-acetylglucosamine was possible with barium hydroxide, a feature attributed to chelate formation between the acetamide carbonyl group and the glycosidic oxygen in the beta-series.
Crich
David
D
Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA. dcrich@uic.edu
Vinod
A U
AU
D000107:Acetylation; D000586:Amination; D003847:Deoxyglucose / Q000737:chemistry*; D005944:Glucosamine / Q000737:chemistry*; D006027:Glycosides / Q000138:chemical synthesis / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D015394:Molecular Structure; D023303:Oxazolidinones / Q000737:chemistry*; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry
D006027:Glycosides; D006878:Hydroxides; D023303:Oxazolidinones; D013438:Sulfhydryl Compounds; D003847:Deoxyglucose; D005944:Glucosamine