title: 5,5-Dihydroxy-barbituric acid 1,4-dioxane hemisolvate.
abstract: The asymmetric unit of the title compound,, C(4)H(4)N(2)O(5)·0.5C(4)H(8)O(2), contains one molecule of 5,5-dihydroxybarbituric acid with a nearly planar barbiturate ring and half a molecule of 1,4-dioxane. The geometry of the centrosymmetric dioxane molecule is close to an ideal chair conformation. The crystal structure exhibits a complex three-dimensional hydrogen-bonded network. Barbiturate mol-ecules are connected to one another via N-H⋯O=C, O-H⋯O=C and N-H⋯O(hydr-oxy) inter-actions, while the barbituric acid mol-ecule is linked to dioxane by an O-H⋯O contact.
authors.affiliation: Institute of Pharmacy, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gelbrich
authors.forename: Denise
authors.initials: D
authors.lastname: Rossi
authors.forename: Ulrich J
authors.initials: UJ
authors.lastname: Griesser