Linezolid-crystal form II

A process to prepare (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide, crystal “Form II” which comprises:

• (1) producing (S)-N-[[3-[3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide 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]acetamide in a solvent or mixture of solvents at a temperature below a temperature of about 80° and
• (3) separating the (S)-N-[[3-3-fluoro-4-(4-morpholinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide crystal “Form II” from the solvent(s).