Acidic ionic liquid [bmim]HSO4: An efficient catalyst for acetalization and thioacetalization of carbonyl compounds and their subsequent deprotection

Acetalization/thioacetalization of carbonyl compounds, under solvent free conditions, has been described using acidic ionic liquid 1-Butyl-3-methylimidazolium hydrogen sulfate ([bmim]HSO4) at room temperature, in conjunction with microwave energy and ammonium chloride. The catalyst retains its acidity, catalytic activity, and recyclability in ammonoium chloride, whereas its decomposition is observed under microwave irradiation. The same catalyst has also been used for the deprotection of acetals, thioacetals as well as for transthioacetalization under microwave irradiation.