ethyl (Z)-2-cyanocyclopropanecarboxylate

ethyl 5-cyano-4,5-dihydro-1H-pyrazole-3-carboxylate

5-ethyl 1-methyl (E)-2-methylpent-2-enedioate

cyclopropane-1,2-dicarboxylic acid 2-ethyl ester 1-methyl ester

3-ethyl 5-methyl 5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylate