Abstract: The protocol for ethyl 2-cyano-2-(1,3-dialkylimidazolidin-2-ylidene)acetate derivatives 3 via one step reaction between bis-substituted heterocyclic ketene aminals (HKAs) 1 and halogen compounds 2 in DMF medium at room temperature and sodium hydride as alkali has been developed.This reaction has the advantages such as operational simplicity,mild reaction conditions and excellent yields (87%—93%).