title: A novel Janus-type AT nucleoside with benzoyl protecting groups forming a pleated-sheet structure.
abstract: The title compound, 5-amino-8-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)pyrimido[4,5-d]pyrimidine-2,4(3H,8H)-dione methanol monosolvate, C(32)H(25)N(5)O(9)·CH(4)O, which crystallized slowly from methanol, exhibits an anti conformation with a glycosyl-bond torsion angle of χ=-141.28 (17)°. The furanose moiety adopts an N-type sugar puckering ((3)T(4)). The corresponding pseudorotation phase angle and maximum amplitude are P=24.5 (2)° and τ(m)=38.3 (2)°, respectively. In the solid state, one methanol molecule acts as a bridge joining adjacent nucleoside molecules head-to-head, leading to a pleated-ribbon supramolecular structure, with the base moieties located in the centre of the ribbon and the sugar residues protruding to the outside of the layers, as in a DNA helix. The pleated-ribbon supramolecular structure is tethered together into a two-dimensional infinite pleated-sheet structure through aromatic stacking between the nucleobase planes and the benzene rings of the benzoyl protecting groups on the 5'-OH group of furanose.
authors.affiliation: Laboratory of Ethnopharmacology, Institute for Nanobiomedical Technology and Membrane Biology, Regenerative Medicine Research Center, West China Hospital, West China Medical School, Sichuan University, No. 1 Keyuansilu, Gaopeng Dadao, Chengdu, Sichuan 610041, People's Republic of China.
authors.forename: Mei Ying
authors.initials: MY
authors.lastname: Pan
authors.forename: Xiao Hua
authors.initials: XH
authors.lastname: Wu
authors.forename: Dai Bing
authors.initials: DB
authors.lastname: Luo
authors.forename: Wen
authors.initials: W
authors.lastname: Huang
authors.forename: Yang
authors.initials: Y
authors.lastname: He
mesh_terms: D020029:Base Pairing; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D015394:Molecular Structure; D009005:Monosaccharides / Q000737:chemistry*; D009705:Nucleosides / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D011744:Pyrimidinones / Q000737:chemistry*
chemical_list: C559650:5-amino-8-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)pyrimido(4,5-d)pyrimidine-2,4(3H,8H)-dione; D009005:Monosaccharides; D009705:Nucleosides; D011743:Pyrimidines; D011744:Pyrimidinones; D004247:DNA