Hydrogen Peroxide → 1-(2,6-Dimethyl-4-nitrophenyl)-3-(2-hydroxyethyl)pyridin-2(1H)-one

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Reaction Steps

With ice-cooling, 1.15 l (575 mmol) of a 0.5 molar solution of 9-borabicyclo[3.3.1]nonane in tetrahydrofuran are added to 70.7 g (262 mmol) of the compound from Example 60A (alternative synthesis) such that the internal temperature does not exceed 10-15° C. The mixture is then warmed to RT and stirred at room temperature for 1.5 h. The mixture is then cooled and, at 0° C.-5° C., 653 ml (1.31 mol) of a 2-molar aqueous solution of sodium hydroxide are added. The mixture is stirred briefly, and 296 g (2.51 mol) of a 30% strength hydrogen peroxide solution are then added such that the temperature does not exceed 30° C. and does not fall below 25° C. After the addition has ended, the mixture is stirred for another 30 min. Water and ethyl acetate are added to the reaction mixture. After phase separation, the aqueous phase is once more extracted with ethyl acetate. The combined organic phases are washed with an aqueous sodium bisulphite solution. The organic phase is removed and evaporated to dryness under reduced pressure. The residue is dissolved in dichloromethane and purified by chromatography on silica gel (cyclohexane/ethyl acetate 1:2, then ethyl acetate). This gives 66.5 g (88% of theory) of the desired product.

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