Process for the preparation of pure enatiomers of 4-[4-(4'-tert.butylphenyl)-2-hydroxybutoxy]-benzoic acid and its alkyl ester.

摘要

The pure enantiomers of LIFIBROL and its alkyl esters can be prepared in surprisingly good yields by reacting the pure enantiomeric forms of S(-)- or R(+)-4-(4'-tert.butylphenyl)-1,2-epoxybutane with alkyl 4-hydroxybenzoate in DMF at increased temperature and in the presence of the sodium salt of alkyl 4-hydroxybenzoate. The crude reaction product is subsequently to be separated off. Either the stereochemically pure LIFIBROL ester is obtained by recrystallisation, or the precipitated LIFIBROL enantiomer is prepared in pure crystalline form by mild alkaline hydrolysis followed by acidification.