| 摘要 |
PROBLEM TO BE SOLVED: To provide a Form I crystalline compound of (-)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one, and a process of obtaining the crystalline compound.SOLUTION: A desired final crystal form, Form I, can be produced when using methanol or ethanol from a solvent and anti-solvent system. Form II is isolated from 2-propanol and can be converted to a desired crystal form at low drying temperatures, such as temperatures from about 40°C to about 50°C. |
