title: Crystal structure of 5,11-di-hydro-pyrido[2,3-b][1,4]benzodiazepin-6-one.
abstract: The title compound, C12H9N3O, is an inter-mediate in the synthesis of the muscarinic M2 receptor antagonist AFDX-384. The seven-membered ring adopts a boat conformation and the dihedral angle between the planes of the aromatic rings is 41.51 (9)°. In the crystal, mol-ecules are linked into [001] chains of alternating inversion dimers formed by pairs of N-H⋯O hydrogen bonds and pairs of N-H⋯N hydrogen bonds. In both cases, R 2 (2)(8) loops are generated.
authors.affiliation: The German University in Cairo, Department of Pharmaceutical Chemistry, New Cairo City, 11835 Cairo, Egypt.
authors.forename: Noura M
authors.initials: NM
authors.lastname: Riad
authors.affiliation: The German University in Cairo, Department of Pharmaceutical Chemistry, New Cairo City, 11835 Cairo, Egypt.
authors.forename: Darius P
authors.initials: DP
authors.lastname: Zlotos
authors.affiliation: Institute of Pharmacy and Food Chemistry, Wuerzburg University, 97074 Wuerzburg, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Holzgrabe
keywords: boat conformation; crystal structure; hydrogen bonding; pyridobenzodiazepine