The X-ray crystal and molecular structure of 5′-bromo-5′-deoxythymidine

5′-Bromo-5′-deoxythymidine (1) crystallizes with four molecules in a monoclinic unit cell of space group C2. The ribose ring adopts an envelope conformation, transient between T and E₀ (O4′-exo), with the C1′ atom being in the flap position. In the crystal lattice, the molecules are connected by intermolecular one-dimensional chains of hydrogen bondings from the hydroxyl hydrogen H3′(O3′) to the carbonyl oxygen O4. The differences in conformation and a hydrogen-bonding system of 1 with comparison to the structure of thymidine are observed. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9: 591–596, 1998