Compounds of formula (I): ##STR1## (in which R.sup.1 is alkoxy, R is alkyl, haloalkyl, alkylamino, cycloalkyl or optionally substituted phenyl, X is chlorine or fluorine and Y is selected from certain specific heterocycles) have excellent antibacterial activity. They may be prepared by introducing the group represented by Y into the corresponding compound in which Y is replaced by a halogen atom.
式(I)的化合物:##STR1##(其中R.sup.1是烷氧基,R是烷基,卤代烷基,烷基
氨基,环烷基或可选取代的苯基,X是
氯或
氟,Y是选自某些特定杂环的基团)具有优异的抗菌活性。它们可以通过将Y所代表的基团引入相应的化合物中来制备,其中Y被卤素原子取代。