Eine einfache Methode zur Herstellung von Benzoxazolen

A Facile Method for the Synthesis of Benzoxazoles The preparation of benzoxazoles by a facile one-pot reaction is reported. The reaction of carboxylic acids with 2-chloro-N-methyl-Δ¹-pyrrolinium chloride in an excess of N-methyl-2-pyrrolidone afforded carboxylic acid chlorides which were converted subsequently to their 2-hydroxyanilides by addition of 2-aminophenols. Cyclization of the 2-hydroxy-anilides at elevated temperatures furnished the benzoxazoles in high yield and purity.