Patent ID: 6855820

Claim:
A process for preparing optically pure (+)-(2S, 3S)-2-(3-chlorophenyl)-3,5,5-trimethyl-2-morpholinol or a pharmaceutically acceptable salt or solvate thereof which comprises treating racemic 2-(3-chlorophenyl)-3,5,5-trimethyl-2-morpholinol with di-p-toluyl-L-tartaric acid under suitable reaction conditions and in a solvent to form a mixture of diastereomeric salts, wherein the solvent comprises at least one solvent selected from the group consisting of ethanol, ethanol and water, industrial methylated spirit (IMS), and acetonitrile; isolating from the mixture of the diastereomeric salts a chiral salt of (+)-(2S, 3S)-2-(3-chlorophenyl)-3,5,5-trimethyl-2 -morpholinol; and contacting the chiral salt of (+)-(2S, 3S)-2-(3-chlorophenyl)-3,5,5-trimethyl-2-morpholinol with a base.