Methyl iodide → 5-Bromo-1-methylpyridin-2(1H)-one

Beteiligte Stoffe

Reaktionsschritte

5-Bromopyridin-2(1H)-one (0.250 g, 1.44 mmol) was dissolved in DMF (3 mL) then added iodomethane (0.0943 ml, 1.51 mmol) and potassium carbonate (0.218 g, 1.58 mmol). The reaction was stirred at room temperature overnight. The reaction mixture was concentrated under vacuum. The remaining residue was dissolved in ethyl acetate then washed with water and brine. The aqueous layer was back-extracted with ethyl acetate (3×). The organic layers were combined and dried over sodium sulfate then concentrated under vacuum to afford 5-bromo-1-methylpyridin-2(1H)-one as an orange waxy solid. MS (ESI pos. ion) m/z: 188.0 and 190.0 (MH+). Step 2. 5-Bromo-1-methylpyridin-2(1H)-one (0.100 g, 0.532 mmol) was suspended in dioxane (2 mL) then added 4,4,5,5-tetramethyl-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3,2-dioxaborolane (0.203 g, 0.798 mmol), PdCl2(dppf)-CH2Cl2Adduct (0.0217 g, 0.0266 mmol) and sodium acetate (0.109 g, 1.33 mmol). The reaction mixture was heated at 120° C. for 5.5 hours then at 130° C. for 3 hours. The reaction mixture was filtered through a pad of Celite, washing with MeOH. The filtrate was concentrated under vacuum. The remaining black residue was then dissolved in dichloromethane and filtered through another pad of Celite, washing well with dichloromethane. The filtrate was concentrated under vacuum and the remaining black residue was further dried under high vacuum to afford 1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2(1H)-one as a black solid. MS (ESI pos. ion) m/z: 236.1 (MH+).

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