Hydrochloric Acid → 4-(3-ethoxy-4-hydroxy-5-nitrophenyl)-6-phenyl-5-(pyrazin-2-yl)-3,4-dihydropyrimidin-2(1H)-one

Participants

Reaction Steps

To a solution of 1-phenyl-2-(pyrazin-2-yl)ethanone (Intermediate 26) (150 mg, 0.76 mmol), 3-ethoxy-4-hydroxy-5-nitrobenzaldehyde (149 mg, 0.76 mmol), and urea (137 mg, 2.28 mmol) in 20 mL of ethanol was added 0.2 mL of concentrated HCl solution, the reaction mixture was stirred at reflux for 2 days. After the solvent was removed under reduced pressure, the residue was purified by reverse-phase preparatory HPLC (26-53% acetonitrile+0.1% trifluoroacetic acid in water+0.1% trifluoroacetic acid, over 15 min.) to give Compound 58 (72 mg, yield 21.9%). 1H NMR (DMSO-d6300 MHz): δ10.27 (S, 1H), 9.22 (s, 1H), 8.43 (s, 1H), 8.15 (s, 1H), 7.84 (s, 1H), 7.65 (s, 1H), 7.44 (m, 4H), 7.32 (d, J=7.2 Hz, 3H), 5.45 (d, J=2.1 Hz, 1H), 4.10 (m, 2H), 1.35 (t, J=6.9 Hz, 3H); MS (ESI): m/z 434.0 [M+1]+.

Provenance & Evidence