X-ray structural and n.m.r.-spectral studies of methyl alpha-L-evalopyranoside: reassignment of anomeric configuration for the methanolysis product of methyl 6-deoxy-3-C-methyl-alpha-L-mannofuranoside.
The methanolysis product of methyl 6-deoxy-3-C-methyl-alpha-L-mannofuranoside has been reassigned as methyl 6-deoxy-3-C-methyl-alpha-L-mannopyranoside by X-ray crystallographic and n.m.r.-spectral analyses. The crystals of methyl alpha-L-evalopyranoside are monoclinic, space group C2, with cell dimensions: a = 12.913(2), b = 8.052(1), c = 9.766(2) A, B = 105.13(2) degrees. The pyranoside ring exists in the 1C4 conformation, with the methoxyl and 3-C-methyl groups axial. Nuclear Overhauser effects were measured for selected proton resonances in the 1H-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-1.
Giuliano
R M
RM
Department of Chemistry, Villanova University, PA 19085.
Kasperowicz
S
S
Boyko
W J
WJ
Rheingold
A L
AL
D002236:Carbohydrate Conformation; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008759:Methylglycosides; D008766:Methylmannosides; D008958:Models, Molecular; D014961:X-Ray Diffraction
D008759:Methylglycosides; D008766:Methylmannosides; C059670:methyl 6-deoxy-3-methylmannopyranoside