[BMIM][HSO4] Ionic liquid catalyzed solvent-free microwave assisted one-pot multicomponent synthesis of tetrahydrobenzo[b]Pyran Derivatives

Abstract

We present a simple and environmentally friendly protocol for synthesizing tetrahydrobenzo[b]pyran derivatives through multicomponent condensation of dimedon, malononitrile, and various aromatic aldehydes in the presence of 1-ethyl-3- methylimidazolium hydrogen sulphate [BMIM][HSO4] as a catalyst under microwave irradiation. The one-pot synthesis, simple solventfree conditions, and high isolated yield demonstrate the usefulness of this green technique. The structural features are determined utilizing analytical approaches like Fourier Transform Infrared Spectroscopy (FT-IR) and 1H and 13C Nuclear Magnetic Resonance (NMR) Spectroscopy. To maximize yield, electronic synthesis of tetrahydrobenzo[b]pyran derivatives was performed employing the catalytic activity of 1-ethyl-3-methylimidazolium hydrogen sulphate.