A New Synthesis of 1-Aryl-5-cyano-1H-pyrazole-4-carboxylic Acid Ethyl Esters.

A novel conversion of 5-amino-1-aryl-1H-pyrazole-4-carboxylic acid, ethyl esters to the corresponding 5-cyano esters is described. The process involves nonaqueous diazotization of the amine to form the methyl thioether, which is oxidized to the methyl sulfone, which, in turn, is displaced by cyanide ion. The cyano esters are precursors to chemical hybridizing agents in wheat and barley.