Nitriles in Heterocyclic Synthesis. Novel Synthesis of Pyridazine Derivatives

Abstract
The crotononitriles 1a–c coupled with arenediazonium salts to yield either the acyclic mono- or dihydrazones depending on coupling reaction conditions. Both mono- and dihydrazones could be cyclized to the corresponding pyridazine derivatives. Direct formation of pyridazines on coupling 1b and 1c with arenediazonium salts was observed. Structures of reaction products are confirmed by spectral and analytical data.