Crystal and molecular structure of methyl 4-O-methyl-beta-D-ribo-hex-3-ulopyranoside.
Methyl 4-O-methyl-beta-D-ribo-hex-3-ulopyranoside (2), a model compound for partially oxidized anhydroglucose units in cellulose, was crystallized from CHCl(3)/n-hexane by vapor diffusion to give colorless plates. Crystal structure determination revealed the monoclinic space group P2(1) with Z = 2C(8)H(14)O(6) and unit cell parameters of a = 8.404(2), b = 4.5716(10), c = 13.916(3)A, and beta = 107.467(4) degrees. The structure was solved by direct methods and refined to R = 0.0476 for 1655 reflections and 135 parameters. The hexulopyranoside occurs in a distorted chair conformation. Both hydroxyls are involved in hydrogen bonding and form zigzag bond chains along the b-axis. One of the two hydrogen bonds is bifurcated. The solid-state (13)C NMR spectrum of exhibits eight carbon resonances, with well-separated signals for the two methoxyls (1-OMe: 55.72 ppm, 4-OMe: 61.25 ppm) and a keto resonance with relatively large downfield shift (206.90 ppm). Differences in the C-4 and the methoxyls' chemical shifts in the solid and liquid states were found.
Institute of Chemistry, Christian Doppler-Laboratory, University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
Immanuel
I
Adorjan
Thomas
T
Rosenau
Antje
A
Potthast
Paul
P
Kosma
Kurt
K
Mereiter
Jutta
J
Pauli
Christian
C
Jäger
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002482:Cellulose / Q000737:chemistry; D003460:Crystallization; D018360:Crystallography, X-Ray; D005960:Glucosides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data
D005960:Glucosides; C492893:methyl 4-O-methylhex-3-ulopyranoside; D002482:Cellulose