6-Aza-2′-deoxy­uridine and N³-anisoyl-6-aza-2′-deoxy­uridine

In 2-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,4-triazine-3,5(2H,4H)-dione (6-aza-2′-deoxy­uridine), C₈H₁₁N₃O₅, (I), the conformation of the glycosylic bond is between anti and high-anti [χ = −94.0 (3)°], whereas the derivative 2-(2-deoxy-β-D-erythro-pentofuranosyl)-N⁴-(2-methoxy­benzoyl)-1,2,4-triazine-3,5(2H,4H)-dione (N³-anisoyl-6-aza-2′-deoxy­uridine), C₁₆H₁₇N₃O₇, (II), displays a high-anti conformation [χ = −86.4 (3)°]. The furanosyl moiety in (I) adopts the S-type sugar pucker (²T₃), with P = 188.1 (2)° and τ_m = 40.3 (2)°, while the sugar pucker in (II) is N (³T₄), with P = 36.1 (3)° and τ_m = 33.5 (2)°. The crystal structures of (I) and (II) are stabilized by inter­molecular N—H...O and O—H...O inter­actions.