Studies with 3-Substituted 2-Arylhydrazono-3-Oxoaldehydes: New Routes for Synthesis of 2-Arylhydrazono-3-Oxonitriles,4-Unsubstituted 3,5-Diacylpyrazoles and 4-Arylazophenols

Abstract

Compounds 1a–c reacts with hydroxylamine-O-sulfonic acid or with hydroxylamine hydrochloride in aqueous acetic acid in the presence of sodium acetate to yield the 3-oxoalkanonitriles 3, which were converted into arylazoisoxazole and 1,2,4-triazine derivatives 10. The hydrazones 1a–c reacted with chloroacetone or with phenacyl bromide in refluxing ethanol and in presence of K₂CO₃ to yield the pyrazoles 12a–e, formed most likely via intermediately formed 11a–e. The reaction of 1a,b with acetone afforded the arylazophenols.