DOI: 10.1002/slct.201600167

Static and Dynamic Properties of Fluorinated 4-Aryl-1,5-Benzodiazepinones

Six 4-aryl-6,7,8,9-tetrafluoro-1,5-benzodiazepine-2-ones have been synthesized and fully characterized by ¹H, ¹³C, ¹⁵N and ¹⁹F NMR in solution and in the solid state. In addition, the structures of three of them have been determined by X-ray crystallography. The imine/enamine tautomerism has been experimentally studied by NMR in solution (in the solid state, only the imino tautomer is present). Three barriers corresponding to the inversion of the seven-membered ring have been determined (N1-unsubstituted derivatives). Both for the tautomerism and for the conformational aspects, theoretical calculations at the B3LYP/6-311++G(d,p) level including GIAO calculations of the NMR chemical shifts have been carried out with satisfying results. Different energy profiles have been considered and several transition states located.