The invention relates to antibacterial compounds of formula Iwherein R1represents alkoxy; each of U and V represents CH and W represents CH or N, or U represents N, V represents CH and W represents N, or each of U and V represents N and W represents CH; R2represents hydrogen or fluorine when W represents CH or R2represents hydrogen when W represents N; A represents O or CH2; Y represents CH or N; Q represents O or S; and n represents 0 or 1;and salts of such compounds.本發明係關於一種式I之抗菌化合物:及該等化合物之鹽,其中R1表示烷氧基;U及V各表示CH,且W表示CH或N,或U表示N,V表示CH,且W表示N,或U及V各表示N,且W表示CH;當W表示CH時,R2表示氫或氟,或當W表示N時,R2表示氫;A表示O或CH2;Y表示CH或N;Q表示O或S;及n表示0或1。