| Abstract: | Different aryl substituted acetylenic β-keto cyanides (IAa-o) and β-keto esters (IBa-o) reacted with each of hydrazine hydrate, phenylhydrazine, hydroxylamine hydrochloride and semicarbazide hydrochloride in boiling alcohol to give the same heterocyclic nucleus for each type of ammonia derivative. In certain cases, intermediate acetylenic hydrazides were isolated at room or zero temperatures and cyclized to give the appropriate pyrazol-5-one compounds when healed above their melting points. It is concluded that Michael addition is favoured at elevated temperatures and Claisen addition is favoured at lower temperatures. |
