Resolution of (±)-methyl phenyl[4-[4-[[[4'(trifluoromethyl)-2- biphenylyl]carbonyl]amino]phenyl]-1-piperidinyl]acetate

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 by 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.