Crystal forms of (-)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one
The instant invention describes a method for crystallizing (−)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one from a solvent and anti-solvent solvent system and producing the crystalline product. The desired final crystal form, Form I, can be produced when using methanol or ethanol. Form II is isolated from 2-propanol and can be converted to the desired crystal form at low drying temperatures, such as between about a temperature of 40° C. and 50° C.
1 - 26 . (canceled)
27 . Form I of (−)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one, which is characterized by an X-ray powder diffraction pattern as exhibited in FIG. 3 .
28 . Form II of (−)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one which is characterized by an X-ray powder diffraction pattern as exhibited in FIG. 4 .
29 . Form III of (−)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one which is characterized by an X-ray powder diffraction pattern as exhibited in FIG. 5 .
30 . Form III of (−)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one as recited in claim 29 , which is further characterized by a DSC curve as exhibited in FIG. 6 .
31 . Form III of (−)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one as recited in claim 30 , which is further characterized by a TG analysis as exhibited in FIG. 7