The title compound {systematic name: 4-amino-5-cyclopropyl-7-(2-deoxy-β-D-erythro-pentofuranosyl)-7H-pyrrolo[2,3-d]pyrimidine}, C14H18N4O3, exhibits an anti glycosylic bond conformation, with the torsion angle χ = -108.7 (2)°. The furanose group shows a twisted C1'-exo sugar pucker (S-type), with P = 120.0 (2)° and τm = 40.4 (1)°. The orientation of the exocyclic C4'-C5' bond is -ap (trans), with the torsion angle γ = -167.1 (2)°. The cyclopropyl substituent points away from the nucleobase (anti orientation). Within the three-dimensional extended crystal structure, the individual molecules are stacked and arranged into layers, which are highly ordered and stabilized by hydrogen bonding. The O atom of the exocyclic 5'-hydroxy group of the sugar residue acts as an acceptor, forming a bifurcated hydrogen bond to the amino groups of two different neighbouring molecules. By this means, four neighbouring molecules form a rhomboidal arrangement of two bifurcated hydrogen bonds involving two amino groups and two O5' atoms of the sugar residues.
Keywords: 7-cyclopropyl-2′-deoxytubercidin; 7-deazapurine; crystal structure; cyclopropane; hydrogen bonding; nucleoside.