X-ray structural and n.m.r.-spectral studies of methyl α-l-evalopyranoside: Reassignment of anomeric configuration for the methanolysis product of methyl 6-deoxy-3-C-methyl-α-l-mannofuranoside

✍ Scribed by Robert M. Giuliano; Steve Kasperowicz; Walter J. Boyko; Arnold L. Rheingold

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 390 KB
• Volume: 185
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(89)84021-2

✦ Synopsis

The methanolysis product of methyl 6-deoxy-3-C-methyl-cu-r-mannofuranoside has been reassigned as methyl 6-deoxy3-C-methyl-cr-L-mannopyranoside by X-ray crystallographic and n.m.r.-spectral analyses. The crystals of methyl a-L-evalopyranoside are monoclinic, space group C2, with cell dimensions: a = 12.913(2), b = 8.052(l), c = 9.766(2) A, B = 105.13(2)". The pyranoside ring exists in the 'C, conformation, with the methoxyl and 3-C-methyl groups axial. Nuclear Overhauser effects were measured for selected proton resonances in the 'H-n.m.r. spectrum. Irradiation of the 3-C-methyl and 5-C-methyl group proton signals resulted in enhancements for H-2, H-4, H-5, and the methoxyl group hydrogen atoms, but not for H-l.