PURPOSE: A process for preparing 7 - halo - 1 - cyclopropyl - 6 - fluoro - 4 - oxo - 1,4 - dihydro - £1,8| naphthyridine-3-carboxylate is provided, thereby simply, environment-friendly and cheaply preparing the high purity title compound in higher yield without separation process. CONSTITUTION: A process for preparing 7 - halo - 1 - cyclopropyl - 6 - fluoro - 4 - oxo - 1,4 - dihydro - £1,8| naphthyridine-3-carboxylate of the formula(1) comprises the steps of: reacting a compound of the formula(2) with triethyl orthoformate and anhydrous acetic acid to prepare enol ether; substituting the enol ether with cyclopropyl amine; and cyclizing the substituted enol ether in the presence of a base, wherein R is methyl, ethyl, propyl, iso-propyl, n-butyl, t-butyl, iso-butyl or allyl; and X is fluorine, chlorine or bromine; the amount of the anhydrous acetic acid used is 3 to 15 equivalence to the compound of the formula(2); the amount of the triethyl orthoformate used is 1 to 10 equivalence to the compound of the formula(2); the amount of cyclopropyl amine used is 0.9 to 1.2 equivalence to the compound of the formula(2); the base is selected from triethyl amine, diisopropyl ethyl amine, tributyl amine, N-methyl morpholine, pyridine and 1,8-diazabicyclo£5.4.0|undec-7-ene; the amount of the base used is 1 to 10 equivalence to the compound of the formula(2); and the reaction solvent is selected from acetonitrile, tetrahydrofuran, isopropyl alcohol and dimethyl formamide.
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