1,4-Dihydro-3,5-dicarbethoxycollidine 3,5-Bis(ethoxycarbonyl)-1,4-dihydrocollidine 3,5-Dicarbethoxy-1,4-dihydrocollidine 3,5-Diethoxycarbonyl-1,4-dihydrocollidine 3,5-Pyridinedicarboxylic acid, 1,4-dihydro-2,4,6-trimethyl-, diethyl ester 632-93-9 DDC DDC (porphyrinogen) NSC8910