title: Synthesis, crystal structures and docking studies of 2,7-diphenyl-1,4-diazepan-5-one derivatives.
abstract: BACKGROUND
  1,4-Diazepine derivatives are the seven membered, nitrogen containing heterocyclic ring systems possessing a wide range of therapeutic applications. 1,4-Diazepines attracted the attention of chemists and druggists due to their biological and medicinal properties, such as antimicrobial, anti-HIV and anticancer activities. Herein, we report the preparation, crystal structure determined by X-ray crystallographic methods and docking of the molecules with the potential target protein NS5B RNA polymerase.
  
  
  RESULTS
  The crystal structures and conformational studies of 1,4-diazepine [t-3, t-6-dimethyl-r-2,c-7-diphenyl-1,4-diazepan-5-one(DIAZ1)] and its nitroso derivative [t-3, t-6-dimethyl-1-nitroso-r-2,c-7-diphenyl-1,4-diazepan-5-one(DIAZ2)] are reported. The analyses of the molecules reveal that the seven membered diazepine ring systems adopt chair and boat conformations in compounds DIAZ1 & DIAZ2, respectively. In DIAZ2, the oxygen O2A is disordered over two positions with the refined occupancies of 0.792(7): 0.208(7) in the nitroso group. In both DIAZ1 & DIAZ2, the symmetry related molecules form a hetero/homo-dimer through N-H…O hydrogen bonds.
  
  
  CONCLUSIONS
  In this study, the crystal structures of two new 1,4-diazepines, namely t-3, t-6-dimethyl-r-2,c-7-diphenyl-1,4-diazepan-5-one and t-3, t-6-dimethyl-1-nitroso-r-2,c-7-diphenyl-1,4-diazepan-5-one were synthesized and characterized by X-ray crystallographic methods. The docking studies show that the compounds inhibit at the active site of the target protein and can be utilized as potential drug molecules. In both the compounds, N-H…O hydrogen bonds lead to dimer formation. In DIAZ2, additionally a couple of C-H…O interactions are noted between the molecules. Graphical AbstractStructure and docking studies of 1,4-diazapine derivatives.
authors.affiliation: Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, 600 025 India.
authors.forename: Maheshwaran
authors.initials: M
authors.lastname: Velusamy
authors.affiliation: PG & Research Department of Chemistry, Government Arts College (Autonomous), Coimbatore, 641 018 India.
authors.forename: Sethuvasan
authors.initials: S
authors.lastname: Sreenivasan
authors.affiliation: Department of Physics, Kandaswami Kandar's College, Velur, Namakkal 638 182 India.
authors.forename: Ravichandran
authors.initials: R
authors.lastname: Kandasamy
authors.affiliation: PG & Research Department of Chemistry, Government Arts College (Autonomous), Coimbatore, 641 018 India.
authors.forename: Ponnuswamy
authors.initials: P
authors.lastname: Subbu
authors.affiliation: Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, 600 025 India.
authors.forename: Sugumar
authors.initials: S
authors.lastname: Paramasivam
authors.affiliation: Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, 600 025 India.
authors.forename: Ponnuswamy
authors.initials: P
authors.lastname: Mondikalipudur Nanjappagounder
keywords: 1,4-diazepine(DAP); Hepatitis C virus (HCV); NS5B RNA polymerase; Peptidomimetics