Synthesis of Quinoxaline Derivatives using Sulfonic Acid Functionalized Imidazolium Salts as Highly Efficient and Reusable Bronsted Acidic Ionic Liquids Catalysts under Solvent-free Conditions

Abstract

A simple, highly efficient and green procedure for the condensation of aryl and alkyl 1,2-diamines with α-diketones in the presence of catalytic amount of sulfonic acid functionalized imidazolium salts (SAFIS) is described. Using this method, quinoxaline derivatives as biologically interesting compounds are produced in high to excellent yields and short reaction times. Environmentally benign, simple methodologies, easy workup procedure, clean reaction, short reaction time, high yield and easy preparation of the catalysts are some advantages of this work. In this work, some sulfonic acid functionalized imidazolium salts (SAFIS), as a new category of ionic liquids, are synthesized by eco-friendly and simple procedures, and used as highly efficient and reusable catalysts to promote the following one-pot organic transformations under solvent-free conditions.

Force-Induced Dissolution of Imaginary Mode in Mechanochemical Reaction: Dibenzophenazine Synthesis

“…This reaction is therefore difficult under conventional thermal condition without any catalyst. This is consistent with many experimental reports. − However, under mechanochemical conditions, mechanical action can generate sufficient energy (on the order of eV) locally . Therefore, both the stepwise and concerted paths are possible during grinding.…”

“…DBPZ has been synthesized in various ways. − Conventional syntheses require both a solvent and a catalyst. More specifically, Brønsted acids, ,,,,,,,,, metal oxide nanoparticles, ,,,,,,,,,, and ionic liquids ,,,,, have been used. Recently, however, Carlier et al have synthesized DBPZ using only mechanical ball-milling without any solvent or catalyst and have obtained a very high yield (>99%).…”

“…The quinoxaline structure is an important building block of organic semiconductors and pharmacologically active compounds . DBPZ has been synthesized in various ways. − Conventional syntheses require both a solvent and a catalyst. More specifically, Brønsted acids, ,,,,,,,,, metal oxide nanoparticles, ,,,,,,,,,, and ionic liquids ,,,,, have been used.…”