反应详情

To a solution of 3-amino-thiophene-2-carboxylic acid methyl ester (2.39 g, 15.2 mmol) in benzene (51 mL) was added K2CO3 (6.30 g, 45.6 mmol) followed by ethyl chloroformate (1.74 mL, 18.2 mmol). After heating at reflux for 12 h, the mixture was filtered and the filtrate was concentrated to afford the desired product (3.43 g), which was used in the next step without further purification. MS: 230.0. 1H NMR (400 MHz, CD3OD) δ ppm 7.82 (d, J=5.5 Hz, 1H), 7.66 (d, J=5.6 Hz, 1H), 4.23 (q, J=7.1, Hz, 2H), 3.86 (s, 3H), 1.32 (t, J=7.1 Hz, 3H).

1. temperatureAfter heating
2. temperatureat reflux for 12 h
3. filtrationthe mixture was filtered
4. concentrationthe filtrate was concentrated