An Improved Method for Synthesis of 4,4-Dimethylpyrazolone and Application to Dihydropyridazinone Ring Formation

Abstract

An improved method for 4,4-dimethylpyrazolone synthesis with t-butylcarbazate was described. The applicability of this method to dihydropyridazinone formation was demonstrated. This method is useful for suppressing the side reaction caused by the high nucleophilicity of hydrazine.