SAR OF QUINOLONES 1 Study shows that __ moiety is essential for antibacterial activity 2 The __ must be annulated with aromatic ring 3 Isosteric replacements of __ for carbon atoms at positions __ leads to retention of antibacterial activity 4 Introduction of substituents at position __ greatly reduces or abolishes activity But substitutions at position __ at annulated ring produce good effects 5) __ group at position C5 increases activity 6) __ substitution at position 6 significantly enhance activity 7) __ substitution at position 1 is essential for activity