In this formula (XII), A preferably, or in particular, has themeaning which has already been given in connection with the description of the compounds of the formula (I) according to the invention as being preferred, or particularly preferred, for A. Y.sup.4 and Y.sup.5 are identical or different and representhalogen, preferably chlorine or bromine; alkylsulphonyl, preferably methanesulphonyl; or