Synthesis of novel aryl-1,2-oxazoles from ortho-hydroxyaryloximes

The reaction of ortho-hydroxyaryloximes with p-toluenesulfonyl chloride in the presence of an amine base efficiently generates the corresponding aryl-1,2-oxazole. Investigations revealed that solvent polarity greatly affected the rate of the reaction with faster rates observed in more polar solvents. The reaction proceeds to completion in only a few minutes in acetonitrile at room temperature, and the synthesis of four novel aryl-1,2-oxazoles is presented.