Rapid Access to Synthesis of Bisindole Derivatives Using 2-Morpholino Ethanesulphonic Acid

The present work demonstrates easy and effective synthesis methodology for synthesis of bisindole derivatives in presence of protic organic acid 2-morpholino ethanesulphonic acid (MESA). 2-MESA is water soluble catalyst easy to extract and work-up for the synthesis of bisindole class of compounds. Catalyst is recovered and recycled by simple evaporation of water. Efficient aromatic electrophilic substitution of indoles (2 mmol) with aromatic aldehydes (1 mmol) equipped with various constituents were carried out employing a catalytic amount in ethanol to obtain bisindoles in good to excellent yields.