105897-30-1 2H-1,4-Benzoxazine-5-carboxylic acid, 3,4-dihydro-7-methoxy-2-methylene-3-oxo- 3,4-Dihydro-7-methoxy-2-methylene-3-oxo-2H-1,4-benzoxazine-5-carboxylic acid Degradation product II-F3