Multicomponent synthesis of new barbituric acid derivatives.

A new type of the four-component tandem Knoevenagel—Michael reaction was discovered, which used arylaldehydes, N,N′-dimethylbarbituric acid, dimedone, and morpholine or piperidine in organic solvents or in water. The reaction proceeded under mild conditions at room temperature with the formation of a new substituted unsymmetrical polycyclic ionic scaffold in 83–98% yields. The structures of the reaction products were confirmed by X-ray diffraction analysis on the example of two compounds. The further oxidative cyclization of the Knoevenagel—Michael reaction products led to unsymmetrical substituted dihydrofurans spiro-annulated with N,N′-dimethylbarbituric acid. The structures of the synthesized compounds were confirmed by X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]