Details for Patent: 6,444,813

Title:	Linezolid-crystal form II
Abstract:	The invention is a process to produce a compound, linezolid ##STR1## which is useful as an antibacterial agent.
Inventor(s):	Bergren; Michael S. (Portage, MI)
Assignee:	Pharmacia & Upjohn Company (Kalamazoo, MI)
Filing Date:	Jan 29, 2001
Application Number:	09/772,239
Claims:	1. A process to prepare (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]a cetamide, crystal "Form II" which comprises: (1) producing (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]a cetamide in greater than 98% enantiomeric purity, (2) mixing the greater than 98% enantiomerically pure (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]a cetamide in a solvent or mixture of solvents at a temperature below a temperature of about 80.degree. and (3) separating the (S)-N-[[3-3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]ac etamide crystal "Form II" from the solvent(s). 2. A process according to claim 1 where the enantiomeric purity is greater than 99%. 3. A process according to claim 2 where the enantiomeric purity is greater than 99.5%. 4. A process according to claim 1 where the solvent is selected from the group consisting of compounds of the formula: water, acetonitrile, chloroform, methylene chloride, toluene, R.sub.1 --OH where R.sub.1 is C.sub.1 -C.sub.6 alkyl, R.sub.1 --CO--R.sub.2 where R.sub.2 is C.sub.1 -C.sub.6 alkyl or phenyl substituted with 1 thru 3 R.sub.1 where R.sub.1 is as defined above, and where R.sub.1 is as defined above, R.sub.1 --CO--O--R.sub.2 where R.sub.1 is C.sub.1 -C.sub.6 alkyl and R.sub.1 is as defined above, R.sub.1 --O--R.sub.2 where R.sub.1 is C.sub.1 -C.sub.6 alkyl and R.sub.1 is as defined above. 5. A process according to claim 4 where the solvent is selected from the group consisting of water, ethyl acetate, methanol, ethanol, propanol, i-propanol, butanol, acetonitrile, acetone, methyl ethyl ketone, chloroform, methylene chloride, toluene, xylene, diethyl ether, or methyl-t-butyl ether. 6. A process according to claim 4 where the solvent is selected from the group consisting of ethyl acetate, acetone, acetonitrile, propanol, or isopropanol. 7. A process according to claim 4 where the solvent is ethyl acetate. 8. A process according to claim 1 where the (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]a cetamide is mixed for at least 10 min in the solvent or mixture of solvents. 9. A process according to claim 8 where the (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]a cetamide is mixed for at least 20 min in the solvent or mixture of solvents. 10. A process according to claim 8 where the linezolid is mixed for at least 30 min in the solvent or mixture of solvents. 11. A process according to claim 1 where the temperature is less than about 75.degree.. 12. A process according to claim 8 where the temperature is from about 45.degree. to about 60.degree.. 13. A process according to claim 1 where the (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]a cetamide is isolated as a solid before mixing with a solvent or mixture of solvents. 14. A process according to claim 1 where the (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]a cetamide is kept in solution