Application of Green Chemistry in Synthesis of Functionalized Thiopyran via One-pot Multicomponent Reactions in Water

An efficient synthesis of 2H -thiopyran-3,4-dicarboxylate derivatives via one-pot reactions between acetylenic esters, arylisothiocyanates and enaminones in water is described. The advantages of this work were: (1) the reaction was performed under neutral and more important in water as the solvent. (2) No catalyst was required for this reaction. (3) The simplicity of the present procedure made it an interesting alternative to the complex multistep approaches.