7-deaza-2 `-deoxyinosine: a nucleoside showing ambiguous base-pairing properties against the four canonical DNA constituents

Abstract

The title compound [systematic name: 7-(2-deoxy-beta-D-erythropentofuranosyl)- 3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4- one], C(11)H(13)N(3)O(4), represents an acid-stable derivative of 2 `-deoxyinosine. It exhibits an anti glycosylic bond conformation, with a chi torsion angle of 113.30 (15)degrees. The furanose moiety adopts an S-type sugar pucker (4)T(3), with P = 221.8 (1)degrees and tau(m) = 40.4 (1)degrees. The conformation at the exocyclic C4'-C5' bond of the furanose ring is ap (trans), with gamma = 167.14 (10)degrees. The extended structure forms a three-dimensional hydrogen-bond network involving O-H center dot center dot center dot O, N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds. The title compound forms an uncommon hydrogen bond between a CH group of the pyrrole system and the ring O atom of the sugar moiety of a neighbouring molecule.