A Rapid and Efficient Method for Dehydration of Primary Amides to Nitriles. Preparation of Acrylonitrile Derivatives

Abstract

Chloromethylene iminium salts (Vilsmeier reagents) have a long history and thoroughly investigated chemistry⁽¹⁾. Chloro-N, N-dimethylforminium chloride 1 is most conveniently generated by the reaction of N, N-dimethylformamide (DMF) with oxalyl chloride⁽²⁾. The reagent has also been obtained usingthicnyl chloride at elevated temperature and a variety of acid chlorides^(1b). The literature describes several examples of the use of thionyl chloride in combination with DMF in which 1 or a related species is thought to function as the reactive intermediate in the transformation of amides to nitriles⁽³⁾.