“…A detailed knowledge of the conformation of the monomeric nucleoside (1) is compulsory to control and refine the initial parameters used in the design of the anticipated triplex structure. Since only three structures of a-ribofuranosides have been reported so far {a-5-acetyl-2'-deoxyuridine (Hamor, O'Leary & Walker, 1977), (Shefter, Kotick & Bardos, 1967) and (S)-2-amino-9-(2-deoxy-/3-D-ribofuransyl)-4-methyl-l,2,4-triazolin-5-one hydrate (Revankar et al, 1990)}, this contribution also helps in determining general structural aspects of this class of nucleosides.…”