title: The X-ray crystal structure of 2,3:4,5-di-O-isopropylidene-1-O-methyl-beta-D-fructopyranose.
abstract: 2,3:4,5-Di-O-isopropylidene-1-O-methyl-beta-D-fructopyranose, C13H22O6, Mr = 274.3, orthorhombic, P212121, a = 12.388 (2), b = 13.307 (5), c = 8.660 (1) A, V = 1427.4 (9) A3, Z = 4, Dm = 1.24 g.cm-3, Dx = 1.276 g.cm-3, CuKalpha, lambda = 1.54184 A, mu = 8.0 cm-1, F(000) = 592, T = 295 (1) K, R = 0.032 for 1586 observations (of 1693 unique data). The molecule is a derivative of the naturally occurring carbohydrate D-fructose. The data reported here indicate that the ketose six-membered ring is constrained by the presence of two fused five-membered rings into the 3SO conformation. These findings agree with the n.m.r.-spectroscopic results for 2,3:4,5-di-O-benzylidene-beta-D-fructopyranose. As a result of crystal packing forces, the exocyclic side-chain has a C-C-O-C torsion angle of -102 degrees, quite different from the expected value of 180 degrees.
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge 70803.
authors.forename: S F
authors.initials: SF
authors.lastname: Watkins
authors.forename: S J
authors.initials: SJ
authors.lastname: Kim
authors.forename: F R
authors.initials: FR
authors.lastname: Fronczek
authors.forename: R J
authors.initials: RJ
authors.lastname: Voll
authors.forename: E S
authors.initials: ES
authors.lastname: Younathan
mesh_terms: D002236:Carbohydrate Conformation; D005632:Fructose / Q000031:analogs & derivatives* / Q000032:analysis; D014961:X-Ray Diffraction
chemical_list: D005632:Fructose; C064409:2,3-4,5-di-O-isopropylidene-1-O-methyl-beta-fructopyranose