9-(1,3-Anhydro-beta-D-psicofuranosyl)adenine.

In the structure of the title compound, C11H13N5O4, the glycosidic torsion angle, chi, is -107.1 (2) degrees [nucleic acid nomenclature used throughout the manuscript; IUPAC-IUB Joint Commision on Biochemical Nomenclature (1983). Eur. J. Biochem. 131, 9-15], indicating the anti conformation. The furanosyl ring adopts an N-type sugar pucker with the following pseudorotational parameters: PN = 50.5 (2) degrees and nu max = 34.9 (1) degrees. The conformation around the C5'-C6' bond is ap (gauche,trans; gt; -g), with a torsion angle gamma of 176.28 (19) degrees. The 1',2'-oxetane ring is not planar but folded along C3'...C1', with an angle of 9.6 (1) degrees.