A new synthesis of 2‐pyrazolin‐5‐ones from the condensation of <i>C</i>(α),<i>N</i>‐dilithiophenylhydrazones with diethyl carbonate

Abstract

Abstract C (α), N ‐Dilithiophenylhydrazones were prepared from phenylhydrazones in an excess of lithium diisopropylamide and condensed with diethyl carbonate followed by an acid cyclization to give 2‐pyrazolin‐5‐ones.