反应详情

2-t-Butoxycarbonylamino-4-styryl-thiophene-3-carboxylic acid ethyl ester (0.335 g, 0.848 mmol) was dissolved in anhydrous CH2Cl2 (8 mL). This was treated with trifluoroacetic acid (0.346 mL, 4.49 mmol) and stirred at room temperature for 6 hr. More trifluoroacetic acid (0.346 mL, 4.49 mmol) was added and stirring at room temperature was continued for 30 min. The reaction was neutralized with sat. NaHCO3 (25 mL) and then extracted with CH2Cl2 (2×25 mL). The combined organic layers were washed with H2O (1×25 mL) and brine (1×25 mL). The organic layer was then dried (Na2SO4), filtered and the solvent removed in vacuo. The crude product was purified by flash chromatography (SiO2, 15 EtOAc/85 hexanes) to afford the title compound (0.1298 g, 56%) as an inseparable mixture. MS m/e (CI) 274.0 (M+H)+; 1H NMR (300 MHz, CDCl3): δ ppm 0.85 (d, 1H), 1.32 (m, 4H), 4.26 (m, 1H), 6.75 (s, 1H), 7.18 (m, 4H), 7.35 (d, 1H), 7.52 (d, 1H), 7.66 (d, 1H), 7.78 (s, 1H).

1. stirringstirring at room temperature
2. waitwas continued for 30 min
3. extractionextracted with CH2Cl2 (2×25 mL)
4. washThe combined organic layers were washed with H2O (1×25 mL) and brine (1×25 mL)
5. dry with materialThe organic layer was then dried (Na2SO4)
6. filtrationfiltered
7. customthe solvent removed in vacuo
8. customThe crude product was purified by flash chromatography (SiO2, 15 EtOAc/85 hexanes)