Reaction Steps
A suspension of (E)-4-(4-hydroxy-3-methoxyphenyl)but-3-en-2-one (600 mg, 3.1 mmol) in EtOH (10 mL) was stirred for 5 min at 0° C. A solution of K2CO3 (863 mg, 6.2 mmol) in H2O (5 mL) was added and the reaction mixture was stirred for further 10 min at 0° C. After the dropwise addition of 4-(trifluoromethoxy)-benzaldehyde (473 μl, 3.3 mmol), the orange suspension was heated to reflux for 4 d at 40° C. The solvent was evaporated in vacuo and the resulting residue was purified by flash-chromatography on silica gel (Hexane/EtOAc 2:1) and dried in vacuo to obtain NW351 as a yellow solid (191 mg, 17%). mp: 93-95° C. 1H NMR (300 MHz, CD3OD) δ (ppm): 7.72 (d, 3J=8.4 Hz, 2H, HAr), 7.71 (d, 3J=15.9 Hz, 1H, Hvin), 7.68 (d, 3J=15.6 Hz, 1H, Hvin), 7.27 (d, 3J=8.3 Hz, 2H, HAr), 7.24 (d, 4J=1.9 Hz, 1H, HAr), 7.19 (d, 3J=16.0 Hz, 1H, Hvin), 7.15 (dd, 3J=8.4 Hz, 4J=2.0 Hz, 1H, HAr), 7.02 (dd, 3J=15.9 Hz, 5J=0.99, Hz, 1H, Hvin), 6.83 (dd, 3J=8.2 Hz, 5J=0.9 Hz, 1H, HAr), 3.89 (d, 5J=0.9, 3H, OCH3). 13C NMR (75 MHz, CD3OD) δ (ppm): 191.1 (C), 151.7 (q, 4J (C, F)=1.7 Hz), 151.2 (C), 149.4 (C), 146.4 (CH), 142.4 (CH), 135.4 (C), 131.3 (CH), 128.1 (C), 127.6 (CH), 125.0 (CH), 123.6 (CH), 122.3 (CH), 120.2 (C), 116.7 (CH), 112.2 (CH), 56.5 (OCH3). MS (FAB) m/z: 365.2 (M+). Anal. calcd for C19H15F3O4: C, 62.64; H, 4.15. Found: C, 62.45; H, 4.39%.
