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446-52-6

112253-26-6

Example 3: Synthesis of 1-[4-(1-methoxy-1-methyl-ethyl)-phenyl]-3-(2-piperazin-1-yl-benzo-D-pyrrolidin-2-one (Compound 12) Step 1: 25 g of 1-benzylpiperazine (1) and 10 g of 2-fluorobenzaldehyde (2) were reacted in refluxing dioxane/water (1:2, total volume 90 mL) in the presence of 17 g of K2CO3 for 24 hours. After completion of the reaction, the mixture was cooled to room temperature and extracted with dichloromethane. The organic layer was washed sequentially with water, 5% hydrochloric acid and brine, followed by drying with magnesium sulfate, filtration and concentration in vacuum. Purification by silica gel column chromatography (eluent: 5:1 hexane-ethyl acetate) afforded 20 g of 2-(4-benzylpiperazin-1-yl)benzaldehyde (3) in 89% yield; mass spectrum (AP/CI): m/z 281.1 ([M+H]+, 100%). Step 2: 8 g of 2-(4-benzylpiperazin-1-yl)benzaldehyde (3) was reacted with 4.6 g of NaH (60% mineral oil dispersion) at room temperature for 1 h. Subsequently, 7.3 g of 1-acetyl-pyrrolidin-2-one (4) was added, warmed up to room temperature and stirring was continued for 2 hours. The reaction solution was carefully quenched with methanol at 0°C and the solvent was removed in vacuum. The residue was diluted with water and extracted with dichloromethane. The organic layer was washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuum. Purification by silica gel column chromatography (eluent: 40:1 chloroform-methanol) afforded 7.9 g of 3-[2-(4-benzylpiperazin-1-yl)-benzylidene]-pyrrolidin-2-one (5) in 80% yield; mass spectrum (AP/CI): m/z 348.1 ([M+H]+, 100%). Step 3: 6.3 g of 3-[2-(4-benzylpiperazin-1-yl)-benzylidene]-pyrrolidin-2-one (5) was catalytically hydrogenated with 1.5 g of Pd/C in 100 mL of methanol at 50 psi. Upon completion of the reaction, it was filtered and concentrated in vacuum to afford 3.8 g of 3-(2-piperazin-1-yl-benzylidene)-pyrrolidin-2-one (6) in 82% yield; purified by silica gel column chromatography (eluent: 30:1:0.3 chloroform-methanol-ammonium hydroxide); mass spectrum (AP/CI): m/z 260.1 ([M+H]+, 100%). Step 4: 1.2 g of 3-(2-piperazin-1-yl-benzyl)-pyrrolidin-2-one (6) was mixed with 0.041 g of N,N'-dimethylethylenediamine, 0.088 g of CuI, and 0.96 g of K2CO3 in 6 mL of toluene, and 1.27 g of 1-bromo-4-(1-methoxy-1-methyl- ethyl)-benzene (11) was added, and reacted for 17 h at 110 °C . After completion of the reaction, purification by silica gel column chromatography (eluent: 40:1:0.5 chloroform-methanol-ammonium hydroxide) afforded 1.2 g of the racemate 1-[4-(1-methoxy-1-methylethyl)-phenyl]-3-(2-piperazin-1-yl-benzyl)-pyrrolidin-2-one (12), in 64% yield; mass spectrum (AP/CI): m/z 408.2 ([M +H]+).