(S)-dihydroorotate 155-54-4 4,5-dihydroorotate 4,5-dihydroorotic acid 4-pyrimidinecarboxylic acid 4-pyrimidinecarboxylic acid, hexahydro-2,6-dioxo- 5,6-dihydroorotate DI-H-OROTATE L-4,5-dihydroorotate L-dihydroorotate dihydroorotate hexahydro-2,6-dioxo- hydroorotic acid