title: Alogliptin and its benzoate salt.
abstract: The crystal structure of the free base of the antidiabetic drug alogliptin [systematic name: 2-({6-[(3R)-3-aminopiperidin-1-yl]-3-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl}methyl)benzonitrile], C18H21N5O2, displays a two-dimensional N-H···O hydrogen-bonded network. It contains two independent molecules, which have the same conformation but differ in their hydrogen-bond connectivity. In the crystal structure of the benzoate salt (systematic name: (3R)-1-{3-[(2-cyanophenyl)methyl]-1-methyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl}piperidin-3-aminium benzoate), C18H22N5O2(+)·C7H5O2(-), the NH3(+) group of the cation is engaged in three intermolecular N-H···O hydrogen bonds to yield a hydrogen-bonded layer structure. The benzoate salt and the free base differ fundamentally in the conformations of their alogliptin moieties.
authors.affiliation: Institute of Pharmacy, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria. thomas.gelbrich@uibk.ac.at
authors.forename: Thomas
authors.initials: T
authors.lastname: Gelbrich
authors.forename: Volker
authors.initials: V
authors.lastname: Kahlenberg
authors.forename: Ulrich J
authors.initials: UJ
authors.lastname: Griesser
mesh_terms: D001565:Benzoates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D015394:Molecular Structure; D010880:Piperidines / Q000737:chemistry*; D014498:Uracil / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D001565:Benzoates; D010880:Piperidines; D014498:Uracil; C520853:alogliptin