142689-05-2 3H-2-Benzopyran-7-carboxylic acid, 4,6-dihydro-3,4-dimethyl-5-fluoro-8-hydroxy-6-oxo- 4,6-Dihydro-3,4-dimethyl-5-fluoro-8-hydroxy-6-oxo-3H-2-benzopyran-7-carboxylic acid