A Phosphine-mediated Synthesis of 2,3,4,5-tetra-substituted N-hydroxypyrroles from α-oximino Ketones and Dialkyl Acetylenedicarboxylates Under Ionic Liquid Green-media.

Abstract

The development of multicomponent reactions (MCRs) in the presence of task-specific ionic liquids (ILs), used not only as environmentally benign reaction media, but also as catalysts, is a new approach that meet with the requirements of sustainable chemistry. In recent years, the use of ionic liquids as a green media for organic synthesis has become a chief study area. This is due to their unique properties such as non-volatility, non-flammability, chemical and thermal stability, immiscibility with both organic compounds and water and recyclability. Ionic liquids are used as environmentally friendly solvents instead of hazardous organic solvents. We report the condensation reaction between α-oximinoketone and dialkyl acetylene dicarboxylate in the presence of triphenylphosphine to afford substituted pyrroles under ionic liquid conditions in good yields. Densely functionalized pyrroles was easily prepared from reaction of α-oximinoketones, dialkyl acetylene dicarboxylate in the presence of triphenylphosphine in a quantitative yield under ionic liquid conditions at room temperature. In conclusion, ionic liquids are indicated as a useful and novel reaction medium for the selective synthesis of functionalized pyrroles. This reaction medium can replace the use of hazardous organic solvents. Easy work-up, synthesis of polyfunctional compounds, decreased reaction time, having easily available-recyclable ionic liquids, and good to high yields are advantages of present method.