Unusual amino acids. 5.* synthesis of 3,5-dioxopyrazolidine derivatives

Article abstract of DOI:10.1007/BF02256911

Monohydrazides of 2-R-4-methyl-4-cyclohexene-1, 1-dicarboxylic acids react with trifluoroacetic acid anhydride to give 4-substituted 3,5-dioxopyrazolidines, with phosphorus trichloride to give 4-(2-R-5-chloro-4-methylcyclohexane)-3,5-dioxopyrazolidines, a