title: A locked derivative of 8-aza-7-deazaadenosine.
abstract: The title compound [systematic name: (1S,3S,4R,7S)-3-(4-amino-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-1-hydroxymethyl-2,5-dioxabicyclo[2.2.1]heptan-7-ol], C(11)H(13)N(5)O(4), belongs to a family of nucleosides with modifications in both the sugar and nucleobase moieties: these modifications are known to increase the thermodynamic stability of DNA and RNA duplexes. There are two symmetry-independent molecules in the asymmetric unit that differ significantly in conformation, and both exhibit a high-anti conformation about the N-glycosidic bond, with chi torsion angles of -85.4 (3) and -87.4 (3) degrees . The sugar C atom attached to the nucleobase N atom is -0.201 (4) and 0.209 (4) A from the 8-aza-7-deazaadenine skeleton plane in the two molecules. The molecules are assembled into layers via hydrogen bonds and pi-pi stacking interactions between the modified nucleobases.
authors.affiliation: Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznań, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Pasternak
authors.forename: Ryszard
authors.initials: R
authors.lastname: Kierzek
authors.forename: Zofia
authors.initials: Z
authors.lastname: Gdaniec
authors.forename: Maria
authors.initials: M
authors.lastname: Gdaniec
mesh_terms: D018360:Crystallography, X-Ray; D003839:Deoxyadenosines / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure
chemical_list: D003839:Deoxyadenosines; C035823:4-aminopyrazolopyrimidine-2'-deoxyribofuranoside