It can be prepared in two different ways: 1) The cyclization of 3-nitrobenzaldehyde (I), methyl propiolate (II) and ammonium acetate (III) in refluxing acetic acid gives dimethyl 1,4-dihydro-4-(3-nitrophenyl)pyridine-3,5-dicarbocylate (IV), which is aromatized by hot nitric acid affording dimethyl 4-(3-nitrophenyl)pyridine-3,5-dicarbocylate (V). The hydrolysis of (V) with KOH in refluxing ethanol gives the corresponding diacid (VI), which is decarboxylated by treatment with Cu2O in refluxing Dowterm A yielding 4-(3-nitrophenyl)pyridine (VII) (1). The reduction of (VII) with Fe in ethanol-water-acetic acid affords 4-(3-aminophenyl)pyridine (VIII), which is condensed with diethyl ethoxymethylenemalonate (IX) by heating a 135 C, giving diethyl 3-(4-pyridyl)anilinomethylmalonate (X). The thernal cyclization of (X) in refluxing Dowtherm A yields ethyl 1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline-3-carboxylate (XI), which is finally alkylated and saponified by treatment with NaH and ethyl iodide in DMF (1-3).
2) The thermal cyclization of ethyl 2-[3-(4-pyridyl)anilinomethylene]acetoacetate (XII) gives 1,4-dihydro-4-oxo-7-(4-pyridyl)-3-acetylquinoline (XIII), which is alkylated by treatment with ethyl tosylate (XIV) and K2CO3 in dMF at 100 C yielding 1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-acetylquinoline (XV). Finally the acetyl group of (XV) is oxidized to the corresponding carboxyl residue by treatment with Br2 and NaOH in water.