1,3-Cyclopentanedicarboxylic acid, 1,2-dimethyl-4,5-dioxo-, diethyl ester 1,3-Cyclopentanedicarboxylic acid, 1,2-dimethyl-4,5-dioxo-, diethylester 1,3-Cyclopentanedicarboxylic acid, 4,5-dioxo-1,2-dimethyl-, diethylester 72894-17-8