Structure of 1,5-benzodiazepinones in the solid state and in solution: Effect of the fluorination in the six-membered ring

• Main Authors: Marta Pérez-Torralba, Rosa M. Claramunt, M. Ángeles García, Concepción López, M. Carmen Torralba, M. Rosario Torres, Ibon Alkorta, José Elguero
• Format: Article
• Language: English
• Published: Beilstein-Institut 2013-10-01
• Series: Beilstein Journal of Organic Chemistry
• Subjects: benzodiazepinones; DFT; GIAO calculations; inversion barriers; multinuclear NMR; tautomerism; X-ray structures
• Online Access: https://doi.org/10.3762/bjoc.9.253

Two novel tetrafluorinated 1,5-benzodiazepinones were synthesized and their X-ray structures determined. 6,7,8,9-Tetrafluoro-4-methyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one crystallizes in the monoclinic P21/c space group and 6,7,8,9-tetrafluoro-1,4-dimethyl-1,3-dihydro-2H-1,5-benzodiazepin-2-one in the triclinic P−1 space group. Density functional theory studies at the B3LYP/6-311++G(d,p) level were carried out on these compounds and on four non-fluorinated derivatives, allowing to calculate geometries, tautomeric energies and ring-inversion barriers, that were compared with the experimental results obtained by static and dynamic NMR in solution and in solid state.