Synthesis of hexaprofen [2-(4-cyclohexylphenyl) propionic acid]

A novel preparative method for hexaprofen, which is a potent antiinflammatory agent, is described. Friedel-Crafts reaction of cyclohexylbenzene with ethyl α-chloro-α-(methylthio) acetate1 and α-chloro-α-(methylthio) acetonitrile2 afforded ethyl 2-(methylthio)-2-(4-cyclohexylphenyl) acetate7 and 2-methylthio-2-(4-cyclohexylphenyl) acetonitrile8, respectively. Compounds7 and8 were converted into the corresponding ethyl 2-methylthio-2-(4-cyclohexylphenyl) propionate9 and 2-methylthio-2-(4-cyclohexylphenyl) propionitrile10 by methylation with sodium hydride and methyl iodide. Hexaprofen13 was prepared by hydrolysis of ethyl 2-(4-cyclohexylphenyl) propionate11 and of 2-(4-cyclohexylphenyl) propionitrile12 followed by desulfurization of compounds9 and10.