Multicomponent Assembling of Aldehydes, N,N-Dimethylbarbituric Acid, Malononitrile, and Morpholine Into Unsymmetrical Ionic Scaffold and Its Efficient Cyclization

The new type of the four-component tandem Knoevenagel–Michael reaction was discovered: the transformation of arylaldehydes, N,N′-dimethylbarbituric acid, malononitrile, and morpholine in alcohols and other organic solvents without any other additives at ambient temperature resulted in the selective formation of a new substituted unsymmetrical ionic scaffold with two pharmacology-active heterocyclic rings. This new four-component reaction is a simple and efficient route to a previously unknown substituted ionic unsymmetrical scaffold containing N,N′-dimethylbarbituric acid and morpholine. These ionic scaffolds are promising for various biomedical applications, for example, as anticonvulsants and anti-inflammatory drugs, as well as anti-AIDS agents. In this research, we also accomplished the efficient cyclization of morpholin-4-ium 5-(2,2-dicya-no-1-arylethyl)-1,3-dimethyl-2,6-di-oxo-1,2,3,6-tetrahydro-pyrimidin-4-olates by the action of NBS–NaOAc system, with the formation of 5,7-dimethyl-4,6,8-trioxo-2-aryl-5,7-diazaspiro[2.5]octane-1,1-dicarbonitriles in 83%–98% yields. In the final stage of our research, direct one-pot multicomponent transformation of benzaldehydes, N,N′-dimethylbarbituric acid, and malononitrile into spirobarbituric cyclopropanes was accomplished in 75%–97% yields. The spiro-barbituric cyclopropanes are potentially active as remedies against various inflammatory, infectious, immunological, or malignant diseases.