An improved procedure for the synthesis of indole-2-carboxylic acid esters in excellent yields has been achieved by the condensation of 2-halo aryl aldehydes or ketones and ethyl isocyanoacetate using ionic liquid under controlled microwave irradiation (100 W) at 50 °C. This method offers a number of advantages in terms of methodology, high-product yield, short period of conversion, mild reaction conditions and easy workup.
indole; synthesis; ionic liquid; microwave irradiation