Conformations of Acyclonucleosides: Crystal Structure of 9-(4-Hydroxybutyl)Guanine, an Analogue of Acyclovir

Abstract
9-(4-Hydroxybutyl)guanine is an analogue of acyclovir in which the ether oxygen is replaced by a methylene group. Crystals of the monohydrate belong to the monoclinic space group P21/n with a = 4.350 (1), b = 10.859 (1), c = 23.684 (4) Å, β = 90.65 (1)°. X-ray intensity data were measured with a diffractometer and the structure was determined by direct methods. Least-squares refinement converged at R = 0.055 for 1982 reflections. The side chain is fully extended and almost perpendicular to the guanine base.