title: Four 2-amino-6-aryl-4-methoxy-11H-pyrimido[4,5-b][1,4]benzodiazepines: similar molecular structures but different crystal structures.
abstract: 2-Amino-4-methoxy-6-phenyl-11H-pyrimido[4,5-b][1,4]benzodiazepine, C(18)H(15)N(5)O, (I), and its 6-(2-fluorophenyl)-, 6-(3-nitrophenyl)- and 6-(4-methoxyphenyl)- analogues, viz. C(18)H(14)FN(5)O, (II), C(18)H(14)N(6)O(3), (III), and C(19)H(17)N(5)O(2), (IV), respectively, all adopt molecular conformations which are almost identical, containing boat-shaped seven-membered rings. In each structure, paired N-H...N hydrogen bonds link the molecules into centrosymmetric dimers. In each of (I)-(III), the dimers are further linked, forming a different three-dimensional framework in each case, while in compound (IV) the dimers are linked into sheets. The significance of this study lies in the observation of different crystal structures in four compounds whose molecular structures are very similar.
authors.affiliation: Departamento de Química Inorgánica y Orgánica, Universidad de Jaén, Jaén, Spain.
authors.forename: Ricaurte
authors.initials: R
authors.lastname: Rodríguez
authors.forename: Justo
authors.initials: J
authors.lastname: Cobo
authors.forename: Manuel
authors.initials: M
authors.lastname: Nogueras
authors.forename: John N
authors.initials: JN
authors.lastname: Low
authors.forename: Christopher
authors.initials: C
authors.lastname: Glidewell
mesh_terms: D001569:Benzodiazepines / Q000737:chemistry*; D003461:Crystallography; D015394:Molecular Structure
chemical_list: D001569:Benzodiazepines