反应详情

A stirred solution of 4 g (14.4 mmol) of isopropyl 4-bromo-5-ethylthiophene-2-carboxylate was refluxed in dry dimethylformamide (50 mL) with copper cyanide (1.94 g, 22 mmol) for 8 hours. The cooled mixture was poured into 0.1 M sodium cyanide (500 mL) and extracted with diethyl ether (4×50 mL). The organic layers were washed twice with brine (50 mL) and dried over anhydrous sodium sulfate. The solvents were removed in vacuo. Column chromatography on silica gel (400 g), eluting with hexanes:ethyl acetate 9/1 (v:v) gave isopropyl 2-ethyl-3-cyano-thiophene-5-carboxylate (1.7 g, 53%) as a pale yellow oil. 1H-NMR (DMSO-d6; 300 MHz) δ8.03 (s, 1H), 5.10 (septet, 1H, J=6.2 Hz), 3.04 (q, 2H, J=7.5 Hz), 1.31 (t, 3H, J=7.5 Hz), 1.30 (d, 6H, J=6.2 Hz). Mass spectrum (ESI m/z): Calcd. for C11H13NO2S 224.1 (M+H), found 224.0.

1. extractionextracted with diethyl ether (4×50 mL)
2. washThe organic layers were washed twice with brine (50 mL)
3. dry with materialdried over anhydrous sodium sulfate
4. customThe solvents were removed in vacuo
5. washColumn chromatography on silica gel (400 g), eluting with hexanes