3-(3-fluorophenyl)-2-(hydroxymethyl)-6-methyl-4H-pyrido[1,2-a]pyrimidin-4-one → 3-(3-fluorophenyl)-6-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidine-2-carbaldehyde

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Reaction Steps

A mixture of 3-(3-fluorophenyl)-2-(hydroxymethyl)-6-methyl-4H-pyrido[1,2-a]-pyrimidin-4-one (2.0005 g, 7.037 mmol, Prepared in Example 1) and manganese(IV) oxide (6.118 g, 70.37 mmol) in toluene (46.91 mL) was heated to reflux. After 3 h, the mixture was cooled to rt and filtered through a pad of Celite™. The pad was rinsed with DCM (200 mL). The filtrate was concd under reduced pressure to give an orange solid. The orange solid was suspended in hexane (50 mL), sonicated, and filtered to give 3-(3-fluorophenyl)-6-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidine-2-carbaldehyde as a yellow solid: 1H NMR (400 MHz, DMSO-d6) δ ppm 9.77 (1 H, s), 7.78 (1 H, dd, J=8.6, 7.0 Hz), 7.18-7.68 (5 H, m), 7.06 (1 H, d, J=6.7 Hz), 2.92 (3 H, s); Mass Spectrum (ESI) m/e=283.0 (M+1).

Provenance & Evidence