合成路线1

Substitution of 1,2-difluoro-4-nitrobenzene (I) with benzyl alcohol in the presence of KOH in CH2Cl2 gives 1-benzyloxy-2-fluoro-4-nitrobenzene (II), which is reduced to 4-benzyloxy-3-fluoroaniline (III) by means of H2 and Pt/C in EtOAc. Condensation of aniline (III) with benzyl chloroformate (IV) in the presence of NaHCO3 in acetone/H2O affords carbamate (V), which is cyclized with (R)-glycidyl butyrate (VI) using BuLi in THF at –60 °C to provide the oxazolidinone derivative (VII) . Debenzylation of compound (VII) with H2 over Pd/C in THF/MeOH produces alcohol (VIII), which is condensed with epoxide (IX) in the presence of Na2CO3 in DMF at 100 °C to obtain the corresponding ether (X). N-Deprotection of intermediate (X) by means of H2 over Pd/C in EtOAc/MeOH gives the piperidine derivative (XI), which is finally condensed with the quinolone boron chelate (XII) —prepared by reaction of the quinolone ester (XIII) with B(OH)3 and AcOH in the presence of ZnCl2 at 110 °C — using DIEA in NMP at 85 °C .