Synthesis of Derivatives of 3,5-Dioxopyrazolidine

The reaction of monohydrazides of 2-R-4-methylcyclohex-4-ene-1,1-dicarboxylic acids with ethoxymethylenemalonic acid diethyl ester leads to N-(2,2-diethoxycarbonylethylenyl)hydrazides of 2-R-4-methylcyclohex-4-ene-1,1-dicarboxylic acids, which are acylated by the anhydrides of trifluoroacetic and acetic acids with the formation of derivatives of 3,5-dioxopyrazolidine and 5-oxopyrazoline respectively.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 216–220, February, 2005.