The compounds of the formula 6 are converted into compounds of the formula 7 wherein X is halogen such as chloro or bromo by reaction with chloroform or bromoform in the presence of a base such as potassium t-butoxide, and alkali hydroxide, in the optional presence of a phase transfer catalyst such as a quaternary ammonium or phosphonium salt, for instance, triethylbenzylammonium chloride or tribu