1,N 6-Etheno-2′-deoxytubercidin hemihydrate

Abstract

The title compound [systematic name: 7-(2-de-oxy-β-d-erythro- pentofuranos-yl)-7H-imidazo[1,2-c]pyrrolo-[2,3-d]py-rimi-dine hemihydrate], 2C13H14N4O3·H2O or (I)·0.5H2O, shows two similar conformations in the asymmetric unit. These two conformers are connected through one water mol-ecule by hydrogen bonds. The N-glycosylic bonds of both conformers show an almost identical anti conformation with χ = -107.7 (2)° for conformer (I-1) and -107.0 (2)° for conformer (I-2). The sugar moiety adopts an unusual N-type (C3′-endo) sugar pucker for 2′-de-oxy-ribonucleosides, with P = 36.8 (2)° and Tm = 40.6 (1)° for conformer (I-1), and P = 34.5 (2)° and Tm = 41.4 (1)° for conformer (I-2). Both conformers and the solvent mol-ecule participate in the formation of a three-dimensional pattern with a chain-like arrangement of the conformers. The structure is stabilized by inter-molecular O - H⋯O and O - H⋯N hydrogen bonds,together with weak C - H⋯O contacts. © 2011 International Union of Crystallography.