Combination of AlCl₃, Ionic Liquid, and Microwaves: An Efficient Method for Dehydration and 1,3-Dipolar Cycloaddition: An Unusual Observation in the Presence of Acrylonitrile

Abstract

Use of a combination of ionic liquids in the presence of aluminium chloride and microwave irradiation was shown to be a very efficient and highyielding method for the dehydration of aldoximes and also for 1,3-dipolar cycloadditions. Surprisingly, the presence of acrylonitrile rendered an unusual formation of substituted amide.Recently, room-temperature ionic liquids have been used very effectively for various reactions because of their solvating ability, simple workup procedure, and recyclability. Ionic liquids are highly polar but noncoordinating, and they catalyze the reactions, giving better selectivity. [1] Advantages such as rapid reactions, high yields, and selectivity in microwave-assisted reactions have become well known in recent years. We have been using this methodology for some other reactions. [2] In our earlier work, [3] indole-2-carboxamide was obtained when Vilsmeier-Haack reagent was treated with indole-2-aldoxime followed by treatment with boiling NaOH. However, treatment with only water furnished the corresponding nitrile. In view of our interest in microwave-assisted reactions and the importance of ionic liquids as solvents, we decided to use them in combination for a dehydration reaction of aldoximes, and the results Received