Studieswith arylhydrazono-3-oxopropanals: A novel route to synthesis of substituted pyrazoles, oxoalkanonitrile and glyoxalonitrile containing sulfa drugmoieties

A.M.Hussein, I.S.Abdel Hafiz,

Abstract

Coupling of enaminones (1) with diazonium salts gave the hydrazono propanals (3a-h). Compound (3) react with -bromoacetophenone or - chloroacetanilide to yield (5) and (8). These compounds were cyclized smoothly into (6) and (9) respectively. Reactions of phenylhydrazine gave diphenylhydrazones (10) which cyclized into arylazopyrazoles (11) in refluxing pyridine.However, reaction of (3c-f)with hydrazine hydrate afforded pyrazoles (12). Reactions of (3) with phenylhydrazine hydrochloride afforded (11). Finally, reaction of (3c) with hydroxylamine hydrochloride afforded the aldoxime (14) that on refluxing in pyridine gave (15) not (16).