2-Hydroxy-5-carboxymethylmuconate semialdehyde 2461-62-3 5-Carboxymethyl-2-hydroxymuconate semialdehyde 5-Formyl-2-hydroxy-2,4-heptadienedioic acid CARBOXYMETHYL-A-HYDROXYMUCONIC SEMIALDEHYDE, 0- CHMSA CMHMS NSC 318505 delta-Carboxymethyl-alpha-hydroxymuconic semialdehyde