Preparation, characterization and use of 3-methyl-1-sulfonic acid imidazolium hydrogen sulfate as an eco-benign, efficient and reusable ionic liquid catalyst for the chemoselective trimethylsilyl protection of hydroxyl groups

New and novel ionic liquid (3-methyl-1-sulfonic acid imidazolium hydrogen sulfate) is a recyclable and eco-benign catalyst for the chemoselective trimethylsilyl protection of hydroxyl groups under solvent-free conditions to afford trimethylsilanes in excellent yields (92–100%) and in very short reaction times (1–8 min). The catalyst was characterized by FT-IR, 1H NMR and 13C NMR studies. All the products were extensively characterized by 1H NMR, IR, GC–MS and melting point analyses. A mechanism for the catalytic activity is proposed. The catalyst can be recovered and reused without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification.

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► Introducing the new catalyst (as ionic liquid) for organic transformations.
► Superiority of the catalyst with respect to the reported catalysts.
► Introducing an efficient new method for protection of hydroxyl groups.
► Generality of the method, high yields and very short reaction times.
► Application of solvent free conditions in the reaction.