| Abstract: | The title compound, 1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐5‐(prop‐1‐ynyl)pyrimidin‐2,4(1H,3H)‐dione, C12H14N2O5, shows two conformations in the crystalline state: conformer 1 adopts a C2′‐endo (close to 2E; S‐type) sugar pucker and an anti nucleobase orientation χ = ?134.04 (19)°], while conformer 2 shows an S sugar pucker (twisted C2′‐endo–C3′‐exo), which is accompanied by a different anti base orientation χ = ?162.79 (17)°]. Both molecules show a +sc (gauche, gauche) conformation at the exocyclic C4′—C5′ bond and a coplanar orientation of the propynyl group with respect to the pyrimidine ring. The extended structure is a three‐dimensional hydrogen‐bond network involving intermolecular N—H...O and O—H...O hydrogen bonds. Only O atoms function as H‐atom acceptor sites. |
