1,2-Dihydro-2-oxoquinoline-4-carboxylic acid 15733-89-8 2-Hydroxycinchoninic acid 4-Carboxycarbostyril 4-Quinolinecarboxylic acid, 1,2-dihydro-2-oxo- AI3-61768 Cinchoninic acid, 2-hydroxy- EINECS 239-827-9