反应详情

Isopropyl 4-cyano-5-methylthiiophene-2-carboxylate: A stirred solution of 1.9 g (7.3 mmol) of isopropyl 4-bromo-5-methylthiophene-2-carboxylate was dissolved in dry dimethylformamide (30 mL) and refluxed with copper cyanide (785 mg, 8.8 mmol) for 16 hours. The cooled solution was poured into 0.1 M aqueous sodium cyanide solution (300 mL) and extracted with diethyl ether (4×40 mL). The organic layers were washed with brine (2×40 mL), dried over anhydrous sodium sulfate, and the solvents removed in vacuo. Column chromatography on silica gel eluting with hexanes:ethyl acetate 9/1 (v:v), gave isopropyl 4-cyano-5-methylthiophene-2-carboxylate (960 mg, 63%) as a yellow crystalline solid 1H-NMR (DMSO-d6; 300 MHz) δ 8.01 (s, 1H), 5.09 (septet, 1H, J=6.2 Hz), 2.67 (s, 31H), 1.29 (d, 6H, J=6.2 Hz).

1. extractionextracted with diethyl ether (4×40 mL)
2. washThe organic layers were washed with brine (2×40 mL)
3. dry with materialdried over anhydrous sodium sulfate
4. customthe solvents removed in vacuo