| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for crystallizing (-)-6-chloro-4-cycopropylethynyl-4- trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one from a solvent and non- solvent system and obtaining the crystalline product. SOLUTION: The desired final crystal form, form I, can be obtained by forming slurry of the compound by using methanol or ethanol and then adding a specific amount of non-solvent thereto and allowing the slurry to stand at a specific temperature for a specific time. Form II is isolated from 2-propanol and can be converted to the desired crystal form at low drying temperatures (e.g. a temperature of about 40 deg.C to about 50 deg.C). |
