Sodium hydride → Ethyl 1-(2-fluorocyclopropyl)-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate

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Reaction Steps

As for the method for producing the starting materials, an example for the preparation of the compound (IIa) is described below: ##STR7## That is, ethyl 3-ethoxy-2-(2,4,5-trifluorobenzoyl)acrylate (VIa; R4 =C2H5) is reacted with 1-amino-2-fluorocyclopropane (or an acid addition salt thereof such as trifluoroacetate in the presence of at least a molar equivalent of a proper base such as triethylamine), and the resulting ethyl 3-(cis-2-fluorocyclopropyl)amino-2-(2,4,5-trifluorobenzoyl)acrylate (VIIa; R4 =C2H5) can be reacted with approximately a molar equivalent of sodium hydride in a solvent such as anhydrous dioxane at a temperature of from 20° C. to 50° C. to yield ethyl 1-(2-fluorocyclopropyl)-6,7-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate (IIa; R4 =C2H5) in good yield.

Provenance & Evidence