Diethyl (ethoxymethylene)malonate → diethyl [N-cyclopropyl-N-[3-(1-piperazinyl)-4-fluoro-5-methyl-6-nitrophenyl]amino-methylene]malonate

Participants

Reaction Conditions

Reaction Steps

To 3-(1-piperazinyl)-4-fluoro-5-methyl-6-nitro-N-cyclopropylaniline (1.57 g) is added diethyl ethoxymethylenemalonate (1.45 ml) and the mixture is heated at 150° C. for 25 hours. After cooling, the reaction product is purified by silica-gel column-chromatography (dichloromethane:methanol=100:1) to give diethyl [N-cyclopropyl-N-[3-(1-piperazinyl)-4-fluoro-5-methyl-6-nitrophenyl]aminomethylene]malonate (1.50 g). The product is dissolved in acetic anhydride (7.9 ml) and thereto conc. sulfuric acid (3.16 ml) is added dropwise at 50°-60° C., followed by stirring for 30 minutes. The resultant mixture is poured into ice-water, neutralized, extracted with dichloromethane and the extract is dried. The solvent is distilled off under reduced pressure. Purification by silica-gel column-chromatography (dichloromethane:methanol=10:1) to give ethyl 7-(1-piperazinyl)-1-cyclopropyl-6-fluoro-5-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylate (26 mg).

Provenance & Evidence