organic compounds
The title compound {systematic name: 4-amino-1-(2-deoxy--D-erythro-pentofuranosyl)-5-[6-(1-benzyl-1H-1,2,3-triazol-4-yl)hex-1-ynyl]pyrimidin-2(1H)-one}, C24H28N6O4, shows two conformations in the crystalline state, viz. (I-1) and (I-2). The pyrimidine groups and side chains of the two conformers are almost superimposable, while the greatest differences between them are observed for the sugar groups. The N-glycosylic bonds of both conformers adopt similar anti conformations, with = -168.02 (12)° for conformer (I-1) and = -159.08 (12)° for conformer (I-2). The sugar residue of (I-1) shows an N-type (C3'-endo) conformation, with P = 33.1 (2)° and m = 29.5 (1)°, while the conformation of the 2'-deoxyribofuranosyl group of (I-2) is S-type (C3'-exo), with P = 204.5 (2)° and m = 33.8 (1)°. Both conformers participate in hydrogen-bond formation and exhibit identical patterns resulting in three-dimensional networks. Intermolecular hydrogen bonds are formed with neighbouring molecules of different and identical conformations (N-HN, N-H O, O-HN and O-HO).
organic compounds
The title compound [systematic name: 4-amino-1-(2-deoxy-β-D-erythro-pentofuranosyl)-5-ethynylpyrimidin-2(1H)-one], C11H13N3O4, shows two conformations in the crystalline state. The N-glycosylic bonds of both conformers adopt similar conformations, with χ = −149.2 (1)° for conformer (I-1) and −151.4 (1)° for conformer (I-2), both in the anti range. The sugar residue of (I-1) shows a C2′-endo envelope conformation (2E, S-type), with P = 164.7 (1)° and τm = 36.9 (1)°, while (I-2) shows a major C3′-exo sugar pucker (C3′-exo-C2′-endo, 3T2, S-type), with P = 189.2 (1)° and τm = 33.3 (1)°. Both conformers participate in the formation of a layered three-dimensional crystal structure with a chain-like arrangement of the conformers. The ethynyl groups do not participate in hydrogen bonding, but are arranged in proximal positions.