We present experimental and computational studies on the pseudo-Michael reaction of (E)-1-aryl-2-hydrazinyl-
4,5-dihydro-1H-imidazoles with diethyl (ethoxymethylene)malonate (DEEM). The pseudo-Michael reaction leads to
chain adducts, i.e. diethyl [[2-(1-aryl-4,5-dihydro-1H-imidazol-2-yl)hydrazinyl]methylene]propanedioates. This result is
in contrast to our earlier studies on the pseudo-Michael reaction of DEEM with 1-aryl-4,5-dihydro-1H-imidazol-2-amines
which results in imidazo[1,2-α]pyrimidine derivatives even at low temperature without the possibility of isolating chain
intermediates. The structure of all the compounds is confirmed with experimental and computational spectroscopy (1H
and 13C NMR, IR, MS). Furthermore, thermodynamics of the reaction and HOMO-LUMO of the reactants are studied by
using of quantum chemical calculations.