Isobutyl-phenyl-propionic acid prepn. - by reacting isobutyl/benzene with lactic acid sulphonate in presence of acidic catalyst

The prod. 2-(4-isobutylphenyl)-propionic acid (Ibuprofen), is useful for treatment of pain, inflammation and rheumatism. The lactic acid sulphonate is e.g., 2-methanesul-phonyloxylactic acid, 2-benzenesulphonyloxylactic acid or 2-p-toluenesulphonyloxylactic acid. The acidic catalyst may be Friedel-Craft catalyst. Generally, aluminium chloride is pref. The reaction is carried out at 100-160 degrees C for 2-10 hrs. in an organic solvent such as nitrobenzene or s-tetra-chloroethane.