反应详情

A solution of crude (1R,2R)-2-(3,4-dimethoxyphenethoxy)cyclohexane-1-carboxylic acid (167) (3.71 g, 10 mmol) and 4M NaOH aq (10 mL, 40 mmol) in EtOH (25 mL) was stirred at room temperature for 18 hrs. The reaction mixture was then concentrated in vacuo, the residue was re-dissolved in water (25 mL) and the resultant basic aqueous solution was extracted with diethyl ether (2×25 mL). The aqueous layer was collected, acidified to pH1 with 6M HCl aq and extracted with dichloromethane (2×25 mL). The combined organic extracts were dried over anhydrous MgSO4 and concentrated in vacuo to give 2.29 g of (1R,2R)-2-(3,4-dimethoxyphenethoxy)cyclohexane-1-carboxylic acid (168) (74% yield; Rt: 13.48 min (HPLC—method A); 1H-NMR (300 MHz, CDCl3) δ: 7.95 (br s, 1H, CO2H), 6.78-6.69 (m, 3H, Ar), 3.84 (s, 3H, CH3O), 3.82 (s, 3H, CH3O), 3.81 (overlapped dt, J 14 Hz & 7 Hz, 1H, CH2aO), 3.57 (dt, J 14 Hz & 7 Hz, 1H, CH2bO), 3.52-3.42 (m, 1H, CHO), 2.79 (t, J 7 Hz, 2H, CH2), 2.34 (dt, J 14 Hz & 6 Hz, 1H, CHN), 2.13-1.09 (m, 8H, Aliph); MS (ES+) 307.1 [M+H]+.

1. concentrationThe reaction mixture was then concentrated in vacuo
2. dissolutionthe residue was re-dissolved in water (25 mL)
3. extractionthe resultant basic aqueous solution was extracted with diethyl ether (2×25 mL)
4. customThe aqueous layer was collected
5. extractionextracted with dichloromethane (2×25 mL)
6. dry with materialThe combined organic extracts were dried over anhydrous MgSO4
7. concentrationconcentrated in vacuo