Pyrolytic Electrocyclization of Arylmethylidene Derivatives of Glutacononitrile; Synthesis of Dihydroaromatic 1,3-Dinitriles

Abstract

Condensation of seven aromatic aldehydes (1a–g) with glutacononitrile (2) gave 4-(arylmethylidene)pent-2-enedinitriles (3a–g). Flash vacuum pyrolysis of the dinitriles (3a–g) at 750°/0· 02–0·03 mm gives annulated dihydroaromatic 1,3-dicarbonitriles by electrocyclic ring closure of (3). Fully aromatized products formed by secondary loss of H₂ or HCN are also obtained.