Ionic liquids, a new type of solvents for green chemistry, have been studied recently because they are stable, nonvolatile, and easy to recycle. Many important reactions have been carried out in ionic liquids.4 Seddon et al. reported the alkylation of indole in a [bmim]PF6 ionic liquid and obtained almost exclusive N-substituted products. The reaction showed high regioselectivity and gave good yields.5 Encouraged by this, we examined the N-alkylation of 2,4- ...
