Green Protocol for the Synthesis of Bisindolylmethanes and Evaluation of Their Antimicrobial Activities

Abstract

A simple, efficient, and ecofriendly procedure for the preparation of bis(indolyl)methanes via electrophilic substitution reactions of 2-phenylindoles with aldehydes is described. The reaction takes place in the presence of glacial acetic acid and a catalytic amount of anhydrous ferric chloride. All the synthesized compounds have been characterized by elemental analysis and spectral data (IR and ¹H NMR). They have also been evaluated for their antibacterial and antifungal activities, and some of them have shown promising results against S. aureus, E. coli, A. flavus, and A. niger.

Keywords:

• Anhydrous ferric chloride
• bis(indolyl)methanes
• ecofriendly procedure
• electrophilic substitution reaction
• green chemistry techniques
• 2-phenylindole

Dedicated to the late Prof. Vijai N. Pathak.

The authors are thankful to the Head, Department of Chemistry, University of Rajasthan, Jaipur, India for elemental analysis and spectral (IR and ¹H NMR) data. We are also thankful to the Head, Department of Biotechnology, JECRC, Jaipur, India for biological screening of these compounds. One of the authors (A.T.) is also thankful to the Department of Science and Technology (SDST), Jaipur, India for the sanction of the student project.