Sodium Carbonate → Ethyl 7-aminothieno[2,3-b]pyrazine-6-carboxylate

Participants

Reaction Steps

A mixture of 3-chloropyrazine-2-carbonitrile (17.9 g, 128 mmol), sodium carbonate (17.7 g, 167 mmol) and ethyl-2-mercaptoacetate (18.4 mL, 167 mmol) in ethanol (120 mL) was heated to reflux for 4.5 h. Quenched with water (1.5 L) and stirred for 30 min. The resulting precipitate was collected and washed with water. The residue was dissolved in diethyl ether and a black precipitate was filtrated off. Ether was evaporated to give pure compound ethyl 7-aminothieno[2,3-b]pyrazine-6-carboxylate 7 (19.6 g, 68.5%). 1H-NMR (400 MHz, CDCl3) 1.42 (t, J=7.2 Hz, 3H), 4.40 (q, J=7.2 Hz, 2H), 6.19 (br s, 1H), 8.58 (d, J=2.2 Hz, 1H), 8.63 (d, J=2.2 Hz, 1H).

Provenance & Evidence