Synthesis of a novel tricyclic 4‐quinolone. Incorporation of a spiro‐cyclopropyl group at N1 by bridging to C2

An important pharmacophore in many quinolone antiinfectives is the N1 cyclopropane. By incorporating the cyclopropane into a N1 to C2 bridge, the first quinolone substrate incorporating a spiro fused cyclopropane, 8,9,10‐trifluoro‐2,3,4,6‐tetrahydro‐6‐oxospiro[1 H ‐benzo[ c ]quinolizine‐1,l‐cyclopropane]‐5‐carboxylic acid, ethyl ester ( 8 ), was prepared.