STRUCTURE OF 1-(BETA-D-ARABINOFURANOSYL)-6-METHYLCYTOSINE

C10H15N3O5, M(r) = 257.25, orthorhombic, P2(1)2(1)2(1), a = 10.235 (2), b = 10.833 (1), c = 10.129 (3) angstrom, V = 1123.0 (3) angstrom 3, Z = 4, D(x) = 1.521 Mg m-3, lambda(Cu K-alpha(1)) = 1.54050 angstrom, mu = 1.002 mm-1, F(000) = 544, T = 295 K, final R = 0.035 for 950 reflections. The sugar conformation and puckering parameters are 3E with P = 18.5-degrees and psi(m) = 21.4-degrees. The N-glycosidic torsion angle chi has a value of -72.7 (3)-degrees in the syn range. The C4'-C5' side-chain conformation is -ap with gamma = -174.5 (4)-degrees. The conformation parameters are in accordance with the IUPAC-IUB Joint Commission on Biochemical Nomenclature [Pure Appl. Chem. (1983), 55, 1273-1280] guidelines.