反应详情

To a solution of [(2-Ethoxycarbonyl-acetyl)-(3-methyl-butyl)-hydrazono]-thiophen-2-yl-acetic acid ethyl ester (12a) (380 mg, 1.0 mmol) in EtOH (6 mL) at room temperature, sodium ethoxide (Aldrich) (21 wt % in ethanol, 0.4 mL, 1.1 mmol) was added, and the resulting mixture was stirred for 30 min. Aqueous HCl (5%, 0.75 mL) was added slowly, and then followed by liquid-liquid extraction with H2O/EtOAc. The combined organic layer was washed with brine, dried over MgSO4, concentrated under reduced pressure and the residue was purified by flash chromatography on silica gel to give the desired product (13a) (280 mg, 83%) as yellow solid. LC-MS (ESI+): m/e=337.30 [M+1]+(exact ms: 336.11); 1H NMR (400 MHz, CDCl3): δ 7.89 (dd, 1H, J=3.6, 1.2 Hz), 7.39 (dd, 1H, J=5.2, 1.2 Hz), 7.10 (dd, 1H, J=5.2, 3.6 Hz), 4.53 (q, 2H, J=7.2 Hz), 4.22 (m, 2H), 1.73 (m, 2H), 1.68 (m, 1H), 1.50 (t, 3H, J=7.2 Hz), 0.99 (d, 6H, J=6.4 Hz).

1. extractionfollowed by liquid-liquid extraction with H2O/EtOAc
2. washThe combined organic layer was washed with brine
3. dry with materialdried over MgSO4
4. concentrationconcentrated under reduced pressure
5. customthe residue was purified by flash chromatography on silica gel