Ammonia → Methyl 3-(aminomethyl)thiophene-2-carboxylate

A 2-L single-neck round-bottomed flask equipped with a magnetic stirrer and nitrogen inlet was purged with nitrogen and charged with 116c (7.50 g, 32.0 mmol) and a 7 M solution of ammonia in methanol (915 mL, 6.40 mol). The solution was stirred at room temperature for 14 h. After that time, the reaction mixture was concentrated under reduced pressure. The residue was dissolved in water (150 mL) and extracted with methyl tert-butyl ether (2×25 mL). The aqueous layer was basified with sodium hydroxide (5.00 g) and extracted with methyl tert-butyl ether (3×150 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure to afford a 57% yield (3.14 g) of 116d as a colorless oil: 1H NMR (300 MHz, CDCl3) δ 7.45 (d, 1H, J=5.1 Hz), 7.14 (d, 1H, J=5.1 Hz), 4.11 (s, 2H), 3.88 (s, 3H), 1.72 (br s, 2H); MS (ESI+) m/z 172.0 (M+H). The material was used without further purification.