Study of E/Z isomerization of (arylamino)methylidenefuran-2(3H)-ones by 1 H, 13 C, 15 N spectroscopy and DFT calculations in different solvents.

The structure and configuration of the series of previously unknown arylaminomethylidenefuran-2(3H)-ones have been determined in solution by 1 H, 13 C, 15 N nuclear magnetic resonance spectroscopy including two-dimensional experiments such as 1 H─1 H COSY, dqCOSY, 1 H─13 C HSQC, 1 H─13 C HMBC. It was found that synthesized substances exist as an equilibrium mixture of E- and Z-enamines in solution. It was established on the basis of density functional theory calculations that the exchange between the two push-pull enamines is a simple rotation around an exocyclic partial double bond that depends on the effect of the solvents. Copyright © 2017 John Wiley & Sons, Ltd.