Vulgaxanthin II

4-[2-[(1,3-Dicarboxypropyl)imino]ethylidene]-1,2,3,4-tetrahydro-2,6-pyridinedicarboxylic acid

1,2,3,4-Tetrahydro-4-[2-[(1,3-dicarboxypropyl)imino]ethylidene]pyridine-2,6-dicarboxylic acid