A new efficient method for the preparation of intermediate aromatic ketones by Friedel-Crafts acylation

摘要

As the most important method to prepare pharmaceutical and chemical intermediate aromatic ketones, Friedel-Crafts (F-C) acylation is used to seek a novel catalytic system which is imminently consistent with the concept of green chemistry. In this study, six deep eutectic solvents (DES) were synthesized for the Friedel-Crafts acylation reaction as a catalytic solvent. Among the six DES, choline chloride-zinc chloride ([ChCl][ZnCl2](2)) proved to be the most competent candidate of electron-rich arenes with acylation reagent. It got the highest yield when 1.0 equivalent of [ChCl][ZnCl2](2) used with acyl halides at 70 degrees C. Recycled DES was reused directly without any extra process. After five cycles, the catalytic activity did not decrease significantly (80-85%). Finally, according to experimental validation, the possible mechanism of this reaction was considered.