摘要 |
A process for selectively producing an (S)-9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3 dihydro-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid hemihydrate or monohydrate, which comprises controlling the water content of an aqueous solvent in which an (S)-9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl )-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid is dissolved during a crystallization. |