title: Four 2-aryl-8,8-dimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-ones: isolated molecules, hydrogen-bonded dimers, and pi-stacked chains of hydrogen-bonded dimers.
abstract: In each of the three compounds 2-(4-chlorophenyl)-5,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C19H18ClN3O, (I), 2-(4-methoxyphenyl)-5,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C20H21N3O2, (II), and 8,8-dimethyl-2-(4-methylphenyl)-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one monohydrate, C19H19N3O.H2O, (IV), the non-aromatic carbocyclic ring adopts a half-chair conformation, while in 2-(4-chlorophenyl)-8,8-dimethyl-5-phenyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C24H20ClN3O, (III), the corresponding ring adopts a conformation intermediate between the envelope and screw-boat forms. The structure of (I) consists of isolated molecules, while that of (II) contains dimers formed by C-H...O hydrogen bonds. In (III), dimers formed by C-H...O hydrogen bonds are linked into chains by means of an aromatic pi-pi stacking interaction, while in the monohydrate, (IV), the heterocyclic molecules and the water molecules are linked by O-H...O and O-H...N hydrogen bonds to form centrosymmetric four-component aggregates.
authors.affiliation: Departamento de Química, Universidad de Nariño, Ciudad Universitaria, Torobajo, AA 1175, Pasto, Colombia.
authors.forename: Silvia
authors.initials: S
authors.lastname: Cruz
authors.forename: Jairo
authors.initials: J
authors.lastname: Quiroga
authors.forename: José M
authors.initials: JM
authors.lastname: de la Torre
authors.forename: Justo
authors.initials: J
authors.lastname: Cobo
authors.forename: John N
authors.initials: JN
authors.lastname: Low
authors.forename: Christopher
authors.initials: C
authors.lastname: Glidewell
mesh_terms: D018360:Crystallography, X-Ray; D019281:Dimerization; D006860:Hydrogen Bonding; D008745:Methylation; D008958:Models, Molecular; D015394:Molecular Structure; D011799:Quinazolines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D011799:Quinazolines