Synthesis
General procedure for the synthesis of 5-dimethylamino-2-thiophenecarboxaldehyde (30): 5-bromo-2-thiophenecarboxaldehyde (1 g, 5.23 mmol) was mixed with dimethylamine (1.64 mL, 15.69 mmol) in pure water (3 mL). The reaction mixture was stirred at 100 °C for 12 hours. After completion of the reaction, it was extracted with chloroform (50 mL x 2), the organic phases were combined and washed with purified water (50 mL). The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by medium pressure preparative chromatography with ethyl acetate/hexane (1/1, v/v) as eluent to afford the target compound 30 (670 mg, 82.5% yield).1H NMR (300 MHz, CDCl3) δ 3.10 (s, 6H), 5.96 (s, 1H), 7.45 (s, 1H), 9.44 (s, 1H).
References
[1] Synlett, 1998, # 4, p. 383 - 384
[2] Patent: EP2030635, 2009, A1. Location in patent: Page/Page column 26; 50
[3] Chemical Communications, 2015, vol. 51, # 96, p. 17124 - 17127
[4] Patent: CN107090190, 2017, A. Location in patent: Paragraph 0046; 0047; 0048; 0049
[5] Journal of the American Chemical Society, 2001, vol. 123, # 12, p. 2810 - 2824
