[where Hal3 is a halogen atom such as a chlorine atom] by halogen-metal exchange with a base such as n-butyllithium, followed by reaction with a nitrile R13CN, an acid chloride R13COCl or an ester R13CO2Alk5 in a solvent such as tetrahydrofuran at a low temperature e.g. around ???70??? C. and subsequent treatment with an acid such as hydrochloric acid at around ambient temperature.