反应详情

温度

0 °C

5-methyl-2-oxo-cyclohexanecarboxylic acid diethylamide (46) (4.4 g, 21 mmol) was dissolved in diethyl ether (5 mL) and cooled to 0° C. under N2. Bromine (3.32 g, 21 mmol, 1.1 mL) was added dropwise over 15 min and the reaction mixture was allowed to warm to room temperature over 90 min. The mixture was slowly poured into ice-cold saturated aqueous sodium carbonate solution (40 mL) and extracted with ethyl acetate (3×40 mL). The combined organic layers were dried and concentrated in vacuo to afford 6.1 g (quantitative) of 3-bromo-2-hydroxy-5-methyl-cyclohex-1-enecarboxylic acid diethylamide (47) as an off-white solid. The structure was confirmed by 1H NMR (300 MHz, CDCl3) δH 0.8-1.20 (9H, m, CH3 and N(CH2CH3)2), 1.80-2.40 (5H, m, CH2CH(CH3)CH2), 3.15-3.55 (4H, m, N(CH2CH3)2), 4.65-4.74 (1H, m, CHBr), and 12.04 (1H, s, OH).

1. temperatureto warm to room temperature over 90 min
2. extractionextracted with ethyl acetate (3×40 mL)
3. customThe combined organic layers were dried
4. concentrationconcentrated in vacuo