4-Quinolinecarboxylic acid was used in the coupling reaction with diamine linker. A 4-quinolinecarboxylic acid analogue, brequinar sodium was used to inhibit dihydroorotate dehydrogenase and the de novo biosynthesis of pyrimidine. 4-Quinolinecarboxylic acid was used in the coupling reaction with diamine linker. A 4-quinolinecarboxylic acid analogue, brequinar sodium was used to inhibit dihydroorotate dehydrogenase and the de novo biosynthesis of pyrimidine.