Chem. Select 2, 3732–3738 (2017)

DOI: 10.1002/slct.201700405

Curcumin Related 1,4-Diazepines: Regioselective Synthesis, Structure Analysis, Tautomerism, NMR Spectroscopy, X-ray Crystallography, Density Functional Theory and GIAO Calculations

The reaction of 1,2-ethylenediamine with seven fluorinated β-diketones affords two different 1,4-diazepine series depending on the experimental conditions. Their structures as well as tautomerism have been established by 1H, 13C, 15N and 19F nuclear magnetic resonance in solution supported by density functional theory calculations at the B3LYP/6-311++G(d,p) level. The two compounds obtained from (E)-5-(2-fluoro-4-hydroxyphenyl)-1-phenylpent-4-ene-1,3-dione were analyzed by X-ray crystallography and studied by solid-state NMR.