Ionic Liquids: A Class of Versatile Green Reaction Media for the Syntheses of Nitrogen Heterocycles

Ionic liquids have been emerging as a versatile class of green solvents with many projected advantages compared with conventional media. They have been described as “designer solvents” whose properties such as solubility, density, refractive index, and viscosity can be adjusted to suit requirements simply by making changes to the structure of either anion or cation or both. In organic synthesis, ionic liquids have been extensively used for the variety of synthetic transformations. Recently, plethoras of nitrogen heterocycles have been synthesized using variety of structurally diverse ionic liquids. In the present review, I would account the synthesis of various kinds of nitrogen heterocycles using variety of ionic liquids from the beginning to the recent reports.