Synthesis and structural features of new push-pull enamines, 5-aryl-3-[(dimethylamino)methylidene]furan-2(3H)-ones

Conditions were optimized for the synthesis of dimethylaminomethylidene derivatives of furan-2(3H)-ones. This synthesis is based on the reaction of arylfuran-2(3H)-ones and dimethylformamide dimethyl acetal occurring at the methylene group of furanone ring. Effects of the solvent nature and the type of activation (heating at either atmospheric or elevated pressure in a sealed vessel) on the reaction rate and product yields were estimated. NOE NMR experiment allowed us to confirm the existence of 5-aryl-3-[(dimethylamino)methylidene]furan-2(3H)-ones in the form of E-isomers. The structure of one among the products was additionally confirmed using single crystal X-ray diffraction analysis.