Patent ID: 8461341

Claim:
A process for isolating methyl (2S)-phenyl[4-[4-[[[4′-(trifluoromethyl)-2-biphenylyl]carbonyl]amino]phenyl]-1-piperidinyl]acetate or a pharmaceutically acceptable salt thereof from (±)-methyl phenyl[4-[4-[[[4′-(trifluoromethyl)-2-biphenylyl]carbonyl]amino]phenyl]-1-piperidinyl]acetate or an acid addition salt thereof comprising the consecutive steps of a) mixing (±)-methyl phenyl[4-[4-[[[4′-(trifluoromethyl)-2-biphenylyl]carbonyl]-amino]phenyl]-1-piperidinyl]acetate or an acid addition salt thereof with a suitable amount of (S)-N-[(4-methoxyphenyl)sulfonyl]glutamic acid or an alkali or earth alkaline metal salt thereof in a suitable solvent at an elevated temperature; b) cooling the mixture of step a) and collecting the precipitated methyl (2S)-phenyl[4-[4-[[[4′-(trifluoromethyl)-2-biphenylyl]carbonyl]amino]phenyl]-1-piperidinyl]acetate (S)-N-[(4-methoxyphenyl)sulfonyl]glutamic acid salt and setting aside the filtrate comprising methyl (2R)-phenyl[4-[4-[[[4′-(trifluoromethyl)-2-biphenylyl]carbonyl]amino]-phenyl]-1-piperidinyl]acetate (S)—N-[(4-methoxyphenyl)sulfonyl]glutamic acid salt; and c) liberating methyl (2S)-phenyl[4-[4-[[[4′-(trifluoromethyl)-2-biphenylyl]carbonyl]-amino]phenyl]-1-piperidinyl]acetate from the said precipitated salt; and optionally converting methyl (2S)-phenyl[4-[4-[[[4′-(trifluoromethyl)-2-biphenylyl]carbonyl]amino]phenyl]-1-piperidinyl]acetate into a pharmaceutically acceptable salt.