Preparation method of 3-(4-bromophenyl)piperidin-2-one_Kain Industrial Additive

Background and overview^[1]

3-(4-Bromophenyl)piperidin-2-one can be used as a pharmaceutical synthesis intermediate.

Preparation^[1]

3-(4-Bromophenyl)piperidin-2-one is prepared as follows: To ethyl 2-(4-bromophenyl)-5-((tert-butoxycarbonyl)amino)valerate ethyl ester (45.0g, 0.11mol) of 2M ethanol solution of hydrochloric acid (200mL) was added dropwise to 200mL of ethanol. After the dropwise addition was completed, the reaction was stirred for 30 minutes. LC-MS showed that the raw material disappeared. Concentrate to obtain the residue mixed with potassium carbonate (23.0g , 0.15 mol), heated to reflux in ethanol (500 mL) for 18 hours. LC-MS showed that the raw material disappeared. Concentrate most of the ethanol. Mix the residue with 200 mL of water, adjust the pH to 1~2 with 6N hydrochloric acid, and extract with ethyl acetate. (500mL×2), dried, concentrated, and the residue was slurried with petroleum ether to obtain a white solid, which was dried under vacuum to obtain 3-(4-bromophenyl)piperidin-2-one, 23.7g, yield: 83%. 1HNMR (400MHz, MeOD) δ (ppm) 7.53-7.42 (m, 2H), 7.23-7.13 (m, 2H), 3.64 (dd, J=8.2, 6.2Hz, 1H), 3.49-3.35 (m, 2H) , 2.19 (tdd, J=8.7, 6.1, 2.6Hz, 1H), 1.96-1.75 (m, 3H).

Apply^[1]

3-(4-Bromophenyl)piperidin-2-one can be used as a pharmaceutical synthesis intermediate, such as preparation:

The specific steps are as follows: Mix 3-(4-bromophenyl)piperidin-2-one (7.6g, 30mmol) in deuterated methanol (100g), and heat to 40~45°C under nitrogen protection. Add sodium methoxide (3.2g, 60mmol), and react at 40~45°C for 16h. LCMS detection shows that the deuteration rate is 90%. Cool the reaction solution to 20~25°C, add 100mL ammonium chloride solution to quench, and use acetic acid to quench the reaction solution. Extract with ethyl ester (100ml %, LCMS analysis showed a deuteration rate of 92%, and NMR showed a deuteration rate of 94%.