合成路线1

The synthesis of [14C]-labeled clinafloxacin hydrochloride has been reported: The chlorination of 2,4,5-trifluorobromobenzene (I) with lithium diisopropylamide and hexachlorocyclopentadiene gives 3-chloro-2,4,5-trifluorobromobenzene (II), which is carbonated with 14CO2 and butyllithium in ether yielding 3-chloro-2,4,5-trifluoro-3-chlorobenzoic acid (III). The reaction of (III) with SOCl2 affords the corresponding acyl chloride (IV), which is condensed with the dilithium salt of the malonic acid monoethyl ester (V) to give the benzoylacetate (VI). The reaction of (VI) with acetic anhydride and ethyl orthoformate at 120-30 C yields the ethoxymethylene derivative (VII), which by treatment with cyclopropylamine affords the aminomethylene compound (VIII). The cyclization of (VIII) by means of potassium tert-butoxide in DMSO gives 1-cyclopropyl-8-chloro-6,7-difluoro-4-oxo-1,4-dihydroquinoline-3-carbox ylic acid (IX), which is condensed with N-[pyrrolidin-3(S)-yl]carbamic acid tert-butyl ester by means of triethylamine in hot DMSO yielding the protected final product (XI). Finally, this compound is deprotected with 12N HCl in THF.