4-Acetylbenzoic Acid → 4-[3E-{4-Fluoro-3-(thiophen-2-yl)-phenyl}-acryloyl]-benzoic acid

Beteiligte Stoffe

Reaktionsschritte

4-Fluoro-3-thiophen-2-yl-benzaldehyde (1.0 g, 4.85 mmol, from Ex-20A) and 4-acetylbenzoic acid (0.80 g, 4.87 mmol) were dissolved in dimethylformamide (55 mL). Sodium hydroxide solution (5 N, 3.88 mL) was added in one portion, and the mixture was stirred at room temperature for 3 h. The reaction was diluted with water (100 mL) and washed with ethyl acetate (100 mL). The aqueous phase was acidified with conc. HCl and extracted with ethyl acetate (2×100 mL). The organic phase was dried over magnesium sulfate and concentrated under reduced pressure. Recrystallization from ethanol provided 0.90 g (53%) of the title compound as a solid, m.p. 242–244° C. 1H-NMR (300 MHz, d6-DMSO) δ 13.31 (bs, 1H), 8.32 (dd, 1H, J=8.2 and 2.0 Hz), 8.24 (d, 2H, J=8.2 Hz), 8.07 (d, 2H, J=7.9 Hz), 7.98 (d, 1H, J=16.1 Hz), 7.92 (m, 1H), 7.80 (d, 1H, J=16.1 Hz), 7.69–7.73 (m, 2H), 7.41 (dd, 1H, 10.8 and 9.2 Hz), 7.20 (m, 1H). MS m/z=352 ([M]+, 50%), 343 (100%). HRMS (EI) Calcd. for C20H13FO3S: 352.0569. Found: 352.0571.

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