1-Hydroxybenzotriazole → Methyl 3-(4-isobutyrylpiperazine-1-carbonyl)benzoate

Beteiligte Stoffe

Reaktionsschritte

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)+.

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