合成路线1

The reaction of 1-bromo-2,4,5-trifluoro-3-methoxybenzene (I) with CuCN and N-methyl-2-pyrrolidone at 150 C gives 2,4,5-trifluoro-3-methoxybenzonitrile (II), which by treatment with concentrated H2SO4 yields the benzamide (III). The hydrolysis of (III) with H2SO4 - water at 110 C affords 2,4,5-trifluoro-2-methoxybenzoic acid (IV), which by reaction with SOCl2 is converted into the acyl chloride (V). The condensation of (V) with diethyl malonate by means of magnesium ethoxide in toluene affords diethyl 2-(2,4,5-trifluoro-3-methoxybenzoyl)malonate (VI), which by treatment with p-toluenesulfonic acid in refluxing water gives ethyl 2-(2,4,5-trifluoro-3-methoxybenzoyl)acetate (VII). The condensation of (VII) with triethyl orthoformate in refluxing acetic anhydride yields 3-ethoxy-2-(2,4,5-trifluoro-3-methoxybenzoyl)acrylic acid ethyl ester (VIII), which is treated with cyclopropylamine (IX) to afford the corresponding cyclopropylamino derivative (X). The cyclization of (X) by means of NaF in refluxing DMF gives 1-cyclopropyl-6,7-difluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ethyl ester (XI), which is hydrolyzed with H2SO4 in acetic acid to yield the corresponding free acid (XII). Finally, this compound is condensed with 2-methylpiperazine (XIII) in hot DMSO.

合成路线2

The anhydrization of pyridine-2,3-dicarboxylic acid (I) with acetic anhydride gives the corresponding anhydride (II), which by treatment with benzylamine (III) is converted into the benzylimide (IV). The hydrogenation of (IV) with H2 over Pd/C yields 8-benzyl-2,8-diazabicyclo[4.3.0]nonane-7,9-dione (V), which is further hydrogenated with LiAlH4, affording (?-cis-8-benzyl-2,8-diazabicyclo[4.3.0]nonane (VI) (1). The optical resolution of (VI) by separation of the cis-(R,R)-isomer as crystalline L-(+)-tartrate and further purification of the cis-(S,S)-isomer (VII) as the D-(-)-tartrate affords enantiomerically pure (S,S)-8-benzyl-2,8-diazabicyclo[4.3.0]nonane (VII). The debenzylation of (VII) by hydrogenolysis with H2 over Pd/C gives (S,S)-2,8-diazabicyclo[4.3.0]nonane (VIII), which is condensed with 1-cyclopropyl-6,7-difluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (IX) in basic medium and finally salified with HCl. The 1-cyclopropyl-6,7-difluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (IX) has been obtained as follows: The reaction of 2,4,5-trifluoro-3-methoxybenzoyl chloride (X) with malonic acid monoethyl ester monopotassium salt (XI) by means of triethylamine gives 2-(2,4,5-trifluoro-3-methoxybenzoyl)acetic acid ethyl ester (XII), which is condensed with triethyl orthoformate yielding the corresponding ethoxymethylene derivative (XIII). The reaction of (XIII) with cyclopropylamine affords the cyclopropylaminomethylene derivative (XIV), which is finally cyclized to (IX) by means of NaF in DMF.

合成路线3

The condensation of 2,4,5-trifluoro-3-methoxybenzoyl chloride (I) with 14C-labeled diethyl malonate (II) by means of MgCl2 and TEA gives the benzoylmalonate (III), which is monodecarboxylated with TsOH in refluxing water, yielding the benzoylacetate (IV). The reaction of (IV) with triethyl orthoformate and Ac2O at 140 C affords the benzoylacrylate (V), which is treated with cyclopropylamine (VI) in cyclohexane to provide ethyl 3-(cyclopropylamino)-2-(2,4,5-trifluoro-3-methoxybenzoyl)acrylate (VII). The cyclization of (VII) by means of K2CO3 in hot N-methylpyrrolidone gives the quinolone carboxylate (VIII), which is hydrolyzed with NaOH in hot methanol, affording the carboxylic acid (IX). Finally, this compound is condensed with (S,S)-2,8-diazabicyclo[4.3.0]octane (X) by means of 1,4-diazabicyclo[2.2.2]octane (DABCO) in refluxing acetonitrile.

合成路线4

The reaction of 2,4,5-trifluoro-3-methoxybenzoic acid (I) with SOCl2 in toluene gives the corresponding acyl chloride (II), which is condensed with 3-(dimethylamino)acrylic acid ethyl ester (III) by means of TEA to yield 3-(dimethylamino)-2-(2,4,5-trifluoro-3-methoxybenzoyl)acrylic acid ethyl ester (IV). The cyclization of (IV) with 2-fluorocyclopropylamine (V) by means of TEA and K2CO3 in DMF affords the quinolone-3-carboxylate (VI), which is hydrolyzed with HCl in HOAc to provide the carboxylic acid (VII). The reaction of (VII) with BF3/Et2O in diethyl ether gives the boronic ester (VIII), which is condensed with the spiropyrrolidine (IX) by means of TEA in ethanol. Finally, the boronic ester of (IX) is hydrolyzed with HCl to afford the target quinolone-3-carboxylic acid.

合成路线5