The invention relates to antibacterial compounds of formula I wherein R1 represents 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； R2 represents hydrogen or fluorine when W represents CH or R2 represents 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.
