72187-23-6 Dimethyl (2-hexyl-3-oxocyclopent-1-en-4-yl)propanedioic acid Dimethyl (3-hexyl-2-oxo-3-cyclopenten-1-yl)malonate EINECS 276-448-8 Propanedioic acid, (3-hexyl-2-oxo-3-cyclopenten-1-yl)-, dimethyl ester