title: The economical synthesis of [2'-(13)C, 1,3-(15)N2]uridine; preliminary conformational studies by solid state NMR.
abstract: The synthesis of [2'-(13)C, 1,3-(15)N2]uridine 11 was achieved as follows. An epimeric mixture of D-[1-(13)C]ribose 3 and D-[1-(13)C]arabinose 4 was obtained in excellent yield by condensation of K13CN with D-erythrose 2 using a modification of the Kiliani-Fischer synthesis. Efficient separation of the two aldose epimers was pivotally achieved by a novel ion-exchange (Sm3+) chromatography method. D-[2-(13)C]Ribose 5 was obtained from D-[1-(13)C]arabinose 4 using a Ni(II) diamine complex (nickel chloride plus TEMED). Combination of these procedures in a general cycling manner can lead to the very efficient preparation of specifically labelled 13C-monosaccharides of particular chirality. 15N-labelling was introduced in the preparation of [2'-(13)C, 1,3-(15)N2]uridine 11 via [15N2]urea. Cross polarisation magic angle spinning (CP-MAS) solid-state NMR experiments using rotational echo double resonance (REDOR) were carried out on crystals of the labelled uridine to show that the inter-atomic distance between C-2' and N-1 is closely similar to that calculated from X-ray crystallographic data. The REDOR method will be used now to determine the conformation of bound substrates in the bacterial nucleoside transporters NupC and NupG.
authors.affiliation: Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK LS2 9JT.
authors.forename: Simon G
authors.initials: SG
authors.lastname: Patching
authors.forename: David A
authors.initials: DA
authors.lastname: Middleton
authors.forename: Peter J F
authors.initials: PJ
authors.lastname: Henderson
authors.forename: Richard B
authors.initials: RB
authors.lastname: Herbert
mesh_terms: D002247:Carbon Isotopes; D007553:Isotope Labeling; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008968:Molecular Conformation; D009587:Nitrogen Isotopes; D014529:Uridine / Q000031:analogs & derivatives* / Q000138:chemical synthesis*
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D014529:Uridine