1-Ethyl-6,7-dihydroxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid 18465-39-9 3-Quinolinecarboxylic acid, 1,4-dihydro-6,7-dihydroxy-1-ethyl-4-oxo- 6,7-Dihydroxy-1-ethyl-4-oxo-1,2-dihydro-3-quinolinecarboxylic acid BRN 4478907