2,2-Dimethyl-1,3-dioxane-4,6-dione → 4-(3-ethoxy-4-hydroxy-5-nitrophenyl)-6-(1-methyl-1H-pyrazol-4-yl)-5-(thiophen-3-yl)-3,4-dihydropyridin-2(1H)-one

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Reaction Steps

A mixture of 1-(1-methyl-1H-pyrazol-4-yl)-2-(thiophen-3-yl)ethanone (Intermediate 3) (150 mg, 0.73 mmol), 3-ethoxy-4-hydroxy-5-nitrobenzaldehyde (185 mg, 0.87 mmol), meldrum's acid (125 mg, 0.87 mmol) and AcONH4 (84 mg, 1.1 mmol) in AcOH (3 mL) was refluxed under N2 overnight. The mixture was concentrated under reduced pressure and the residue was purified by prep-HPLC (0.1% TFA as additive) to give Compound 4 as yellow solid (20 mg, 6%). 1H NMR (DMSO-d6, 400 MHz): δ 10.20 (s, 1H), 9.43 (s, 1H), 7.62 (s, 1H), 7.42-7.36 (m, 2H), 7.19-7.11 (m, 1H), 7.06 (s, 2H), 6.70-6.68 (m, 1H), 4.11-4.03 (m, 2H), 3.95-3.92 (m, 1H), 3.77 (s, 3H), 3.08 (dd, J=16.4, 7.6 Hz, 1H), 2.60-2.52 (m, 1H), 1.34 (t, J=6.8 Hz, 3H). MS (ESI): m/z 440.9 [M+1]+.

Provenance & Evidence