2-methyl-1-piperazin-1-ylpropan-1-one

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3-(methoxycarbonyl)benzoic acid (0.9 g, 5 mmol) in dichloromethane (20 mL), 1-hydroxybenzotriazole (0.75 g, 5.5 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (1.06 g, 5.5 mmol) and triethyl amine (2 mL) was added. The mixture was stirred at room temperature for 30 min, then 2-methyl-1-(piperazin-1-yl)propan-1-one (1.0 g, 5 mmol) was added and the mixture was stirred at room temperature for 16 h. The resulting mixture was added water (50 mL) and extracted with dichloromethane (100 mL×3). The organic phase was washed with sodium bicarbonate and brine and concentrated. The crude product was purified by column chromatography (silica gel, petroleum ether/ethyl acetate 20:1 to 2:1) to give 1.25 g of methyl 3-(4-isobutyrylpiperazine-1-carbonyl)benzoate as an oil. Yield 94%. 1H-NMR (400 MHz, CDCl3) 1.14-1.15 (d, J=6.4 Hz, 6H), 2.81 (brs, 1H), 3.44-3.80 (m, 8H), 3.94 (s, 3H), 7.52-7.55 (t, J=7.6 Hz, 1H), 7.62-7.64 (d, J=8.0 Hz, 1H), 8.08-8.14 (m, 2H); LC-MS (ESI) m/z: 319 (M+1)+. the mixture was stirred at room temperature for 16 h extracted with dichloromethane (100 mL×3) The organic phase was washed with sodium bicarbonate and brine concentrated The crude product was purified by column chromatography (silica gel, petroleum ether/ethyl acetate 20:1 to 2:1)

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred mixture of 4-formylbenzoic acid (1.5 g, 10 mmol) in anhydrous dichloromethane (30 mL) was added triethylamine (2.52 g, 25 mmol), 1-hydroxybenzotriazole (1.5 g, 11 mmol), followed by 1-ethyl-3-(3-dimethylamino propyl) carbodiimide hydrochloride (2.1 g, 11 mmol). After the addition, the mixture was stirred at room temperature for 40 mins. Then the mixture was cooled to 0° C. and 2-methyl-1-(piperazin-1-yl)propan-1-one (2.12 g, 11 mmol) was added in portion-wise. After the addition, the mixture was allowed to stir at room temperature overnight. The mixture was diluted with dichloromethane (50 mL), washed with saturated citric acid (100 mL×2), followed by saturated sodium bicarbonate (100 mL×2), brine (50 mL), dried over anhydrous sodium sulfate, and concentrated to give 4-(4-isobutyrylpiperazine-1-carbonyl)benzaldehyde (2 g, yield 70%) as a light yellow oil. 1H-NMR (400 MHz, CDCl3) δ (ppm): 1.15 (d, 6H), 2.80 (brs, 1H), 3.39-3.80 (m, 8H), 7.58 (d, J=8.0 Hz, 1H), 7.95 (d, J=8.0 Hz, 1H), 10.07 (s, 1H); LC-MS (ESI) m/z: 289(M+1)+. After the addition Then the mixture was cooled to 0° C. After the addition to stir at room temperature overnight washed with saturated citric acid (100 mL×2) dried over anhydrous sodium sulfate concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred mixture of 4-formylbenzoic acid (1.5 g, 10 mmol) in anhydrous dichloromethane (30 mL) was added triethylamine (2.52 g, 25 mmol), 1-hydroxybenzotriazole (1.5 g, 11 mmol), followed by 1-ethyl-3-(3-dimethylamino propyl) carbodiimide hydrochloride (2.1 g, 11 mmol). After the addition, the mixture was stirred at room temperature for 40 mins. Then the mixture was cooled to 0° C. and 2-methyl-1-(piperazin-1-yl)propan-1-one (2.12 g, 11 mmol) was added in portion-wise. After the addition, the mixture was allowed to stir at room temperature overnight. The mixture was diluted with dichloromethane (50 mL), washed with saturated citric acid (100 mL×2), followed by saturated sodium bicarbonate (100 mL×2), brine (50 mL), dried over anhydrous sodium sulfate, and concentrated to give 4-(4-isobutyrylpiperazine-1-carbonyl)benzaldehyde (2 g, yield 70%) as a light yellow oil. 1H-NMR (400 MHz, CDCl3) δ (ppm): 1.15 (d, 6H), 2.80 (brs, 1H), 3.39-3.80 (m, 8H), 7.58 (d, J=8.0 Hz, 1H), 7.95 (d, J=8.0 Hz, 1H), 10.07 (s, 1H); LC-MS (ESI) m/z: 289(M+1)+. After the addition Then the mixture was cooled to 0° C. After the addition to stir at room temperature overnight washed with saturated citric acid (100 mL×2) dried over anhydrous sodium sulfate concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred mixture of tert-butyl 4-isobutyrylpiperazine-1-carboxylate (6.8 g, 26.5 mmol) in methanol (15 mL) was added hydrochloride/methanol (30 mL, 3M)) at 0° C. After the addition, the mixture was allowed to stir at room temperature overnight. The mixture was concentrated to give 2-methyl-1-(piperazin-1-yl)propan-1-one (5.5 g, yield 100%) as an off-white solid. 1H-NMR (400 MHz, DMSO-d6) δ (ppm): 0.99-1.00 (d, J=6.4 Hz, 6H), 2.84-2.89 (m, 1H), 3.03-3.07 (d, 4H), 3.68-3.74 (d, 4H), 9.58 (s, 2H); LC-MS (ESI) m/z: 157(M+1)+. After the addition The mixture was concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3-formylbenzoic acid (750 mg, 5 mmol) in anhydrous dichloromethane (15 mL) was added triethylamine (1.263 g, 12.5 mmol), 1-hydroxybenzotriazole (0.743 g, 5.5 mmol), followed by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (1.05 g, 5.5 mmol). After the addition, the mixture was stirred at room temperature for 40 mins. Then the mixture was cooled to 0° C., and 2-methyl-1-(piperazin-1-yl)propan-1-one (1.06 g, 5.5 mmol) was added portionwise. After the addition, the mixture was stirred at room temperature overnight. The mixture was diluted with dichloromethane (50 mL), washed with saturated sodium bicarbonate (50 mL×2), 10% citric acid (50 mL), brine (30 mL), dried over anhydrous sodium sulfate, and concentrated to give 3-(4-isobutyrylpiperazine-1-carbonyl)benzaldehyde (1.44 g, yield: 95%) as a gum. LC-MS (ESI) m/z: 289(M+1)+. After the addition Then the mixture was cooled to 0° C. After the addition the mixture was stirred at room temperature overnight washed with saturated sodium bicarbonate (50 mL×2), 10% citric acid (50 mL), brine (30 mL) dried over anhydrous sodium sulfate concentrated