Ethyl chloroformate → Methyl 3-((ethoxycarbonyl)amino)thiophene-2-carboxylate

Participants

Reaction Steps

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).

Provenance & Evidence