Studies on heterocyclic chemistry. Part XIX. Synthesis of 4-aroyl-1-arylpyrazoles from α-aroyl-β-anilinoacrylonitriles and photochemistry of 4-carbonyl-substituted pyrazoles

Abstract

4-Aroyl-1-arylpyrazoles are synthesised by the deamination of 5-amino-4-aroyl-1-arylpyrazoles which are obtained by the reaction of α-aroyl-β-anilinoacrylonitriles with arylhydrazines. These ketones and 1-arylpyrazole-4-carbaldehydes, when irradiated with 2537 Å light, undergo ring transposition and photoreduction, producing 1,2-bis-(1-arylimidazol-4-yl)ethane-1,2-diols.