Sodium Carbonate → Ethyl 7-amino-2-(furan-2-yl)thieno[2,3-b]pyrazine-6-carboxylate

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Reaction Conditions

Reaction Steps

A solution of 3-bromo-6-(furan-2-yl)pyrazine-2-carbonitrile 57 (1.21 g, 4.84 mmol), ethyl-2-mercaptoacetate (0.587 mL, 0.640 g, 5.32 mmol) and sodium carbonate (0.564 g, 5.32 mmol) in ethanol (20 mL) was stirred 1 h at rt, 1 h at 40° C. and 1 h at 50° C. Cooled down to −10° C., the resulting precipitate was collected, washed with cold ethanol (5 mL) and dried to give ethyl 7-amino-2-(furan-2-yl)thieno[2,3-b]pyrazine-6-carboxylate 58 (1.4 g, 100%). NMR (400 MHz, DMSO-d6) 1.32 (t, J=7.0, 3H), 4.33 (q, J=14.0 and 7.0 Hz, 2H), 6.78 (dd, J=3.5 and 2.0, 1H), 7.05 (br s, 2H), 7.47 (dd, J=3.5 and 0.8 Hz, 1H), 8.00 (dd, J=2.0 and 0.8 Hz, 1H), 9.16 (s, 1H). (m/z)=290 (M+H)+.

Provenance & Evidence