A mixture of 1-(3-fluoro-4-methoxyphenyl)-2-phenylethanone (100 mg, 0.41 mmol), 3-ethoxy-4-hydroxy-5-nitrobenzaldehyde (72 mg, 0.34 mmol), urea (61 mg, 1.02 mmol), and concentrated HCl solution (0.03 mL, 0.34 mmol) in EtOH (5 mL) was refluxed overnight. The mixture was evaporated in vacuo, and the residue was purified by preparative HPLC to give Compound 39 (78 mg, yield 48%). 1H NMR (DMSO-d6 400 MHz): δ 10.28 (s, 1H), 8.71 (s, 1H), 7.53 (s, 1H), 7.42 (s, 1H), 7.17 (s, 1H), 7.10-7.01 (m, 5H), 6.95 (d, J=9.2 Hz, 1H), 6.85 (d, J=6.8 Hz, 2H), 5.18 (s, 1H), 4.08-4.01 (m, 2H), 3.79 (s, 3H), 1.33 (t, J=7.2 Hz, 3H); MS (ESI): m/z 480.0 [M+1]+.
