反应详情

A solution of 5-cyanomethyl-thiophene-3-carboxylic acid methyl ester (4.4 g, 22.1 mmol) and NHCO3 (4.1 g, 48.6 mmol) in water (35 mL) and ethanol (35 mL) is heated to reflux for 4 h. After cooling, the reaction mixture is diluted with water and washed with ether. The aqueous layer is acidified with 1 N HCl and extracted with dichloromethane (4×). The combined organic layers are washed with saturated aq NaCl, dried over Na2SO4, filtered and concentrated in vacuo to give 5-cyanomethyl-thiophene-3-carboxylic acid (2.7 g, 73%) as a light yellow solid: mp 154-159° C.; 1H NMR (DMSO-d6, 300 MHz) δ 12.72 (s, 1 H), 8.20 (s, 1 H), 7.30 (s, 1 H), 4.23 (s, 2 H).

1. temperatureto reflux for 4 h
2. temperatureAfter cooling
3. washwashed with ether
4. extractionextracted with dichloromethane (4×)
5. washThe combined organic layers are washed with saturated aq NaCl
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo