Synthesis of Antipyrine Derivatives Derived from Dimedone

摘要

Coupling of dimedone with the diazonium salt of 4-aminoantipyrine afforded 2,3-dimethyl-4-[2-(5,5-dimethyl-2,6-dioxocyclohex-2-ylidend)-hydrazino]-5-OXO-1-phenylpyrazoline(3).Reaction of 3 with excess phenylhydrazine gave the mixed trishydrazone derivative 4.Treatment of 3 with hydroxylamine produced the bisoxime 5 which upon dehydrative cyclization with acetic anhydride gave the corrsponding tetrahydrobenzo[d][1,2,3]triazole derivative 7.A one-pot synthesis of 7 was done by reacting 3 with hydroxylamine hydrochloride in pyridine,followed by heatment with acetic anhydride.