Organic compounds -- part of the class 532-570 series – Organic compounds – Chalcogen in the nitrogen containing substituent
Reexamination Certificate
2005-09-06
2005-09-06
Raymond, Richard L. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Chalcogen in the nitrogen containing substituent
Reexamination Certificate
active
06939964
ABSTRACT:
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.
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Crocker Louis S.
Kukura, II Joseph L.
Stelmach Christine
Thompson Andrew S.
Young Steven D.
Camara Valerie J.
Merck & Co. , Inc.
Raymond Richard L.
Walton Kenneth R.
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