Abstract: The present invention provides a method for producing optically active flurbiprofen. The method of the present invention includes mixing racemic flurbiprofen and (S)- or (R)-3-methyl-2-phenylbutylamine in an organic solvent to produce a diastereomeric salt; and treating the diastereomeric salt with an acid in a second solvent. In the method of the present invention, flurbiprofen having a desired absolute configuration can be obtained very efficiently without repeating the procedure for optical resolution a plurality of times.

Abstract: The present invention provides a method for producing optically active flurbiprofen. The method of the present invention includes mixing racemic flurbiprofen and (S)- or (R)-3-methyl-2-phenylbutylamine in an organic solvent to produce a diastereomeric salt; and treating the diastereomeric salt with an acid in a second solvent. In the method of the present invention, flurbiprofen having a desired absolute configuration can be obtained very efficiently without repeating the procedure for optical resolution a plurality of times.

Abstract: A method for producing an optically active 1-(4-t-butylphenyl)-5-oxo-3-pyrrolidine carboxylic acid and/or an enantiomeric ester thereof which includes treating an ester of (±)-1-(4-t-butylphenyl)-5-oxo-3-pyrrolidine carboxylic acid with an esterase derived from Bacillus brevis 042-24 (FERM BP-5872).

Abstract: Provided is a process for separating (S)- or (R)-2-(3-benzoylphenyl)propionic acid from a mixture of (S)- and (R)-2-(3-benzoylphenyl)propionic acid, which comprises (1) reacting the mixture of (S)- and (R)-2-(3-benzoylphenyl)propionic acid with (S)- or (R)-3-methyl-2-phenylbutylamine in a suitable solvent to form a diastereomer salt of (S)-2-(3-benzoylphenyl)propionic acid with (S)-3-methyl-2-phenylbutylamine or a diastereomer salt of (R)-2-(3-benzoylphenyl)propionic acid with (R)-3-methyl-2-phenylbutylamine; (2) separating the diastereomer salt from the reaction mixture; and (3) liberating the separated diastereomer salt to give (S)- or (R)-2-(3-benzoylphenyl)propionic acid. According to the present process, it is possible to obtain optically active (S)- or (R)-2-(3-benzoylphenyl)propionic acid having 99% or more of high optical purity in a high yield. Thus, the present process is a practical and efficient process which can simplify purification steps and can be applied for an industrial production process.