(2,4-Dichloro-pyrimidin-5-yl)-(2-methylsulfanyl-pyrimidin-4-yl)-methanol → (2,4-Dichloro-pyrimidin-5-yl)-(2-methylsulfanyl-pyrimidin-4-yl)-methanone

To a stirred solution of (2,4-dichloro-pyrimidin-5-yl)-(2-methylsulfanyl-pyrimidin-4-yl)-methanol (13.6 g, 45 mmol) in dichloromethane (160 mL) and methanol (40 mL) was added MnO2 (55 g, 632 mmol), The mixture was heated at reflux for 16 hours. After cooling to room temperature, the precipitate was removed off by filtration. The filtrate was concentrated and the residue was purified by column chromatography (silica, 20 g, 200-300 mesh, eluting with methanol:dichloromethane, 1:200) to afford (2,4-dichloro-pyrimidin-5-yl)-(2-methylsulfanyl-pyrimidin-4-yl)-methanone. (Yield 9.52 g, 71%).