ChemicalBook CAS DataBase List 1-(5-BroMo-2-Methoxypyridin-3-yl)ethanone

1-(5-BroMo-2-Methoxypyridin-3-yl)ethanone synthesis

5synthesis methods

Product Name:1-(5-BroMo-2-Methoxypyridin-3-yl)ethanone
CAS Number:1256811-02-5
Molecular formula:C8H8BrNO2
Molecular Weight:230.06

3-Pyridinecarboxamide, 5-bromo-N,2-dimethoxy-N-methyl-

1190128-69-8

75-16-1

1-(5-BroMo-2-Methoxypyridin-3-yl)ethanone

1256811-02-5

Methylmagnesium bromide (MeMgBr, 10 mL, 30.0 mmol) was added slowly and dropwise to a solution of 5-bromo-N,2-dimethoxy-N-methylnicotinamide (5.0 g, 18.18 mmol) in tetrahydrofuran (THF, 50 mL) at -78 °C. The reaction mixture was stirred at 20 °C overnight. Subsequently, the reaction mixture was quenched by pouring into aqueous ammonium chloride (NH4Cl) solution. The mixture was extracted with ethyl acetate (EtOAc). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (eluent: petroleum ether/ethyl acetate=10:1) to afford 1-(5-bromo-2-methoxypyridin-3-yl)ethanone (3.0 g, 71% yield).1H NMR (CDCl3, 400 MHz) δ 8.33 (d, J=2.4Hz, 1H), 8.19 (d, J=2.4Hz, 1H), 4.03 ( s, 3H), 2.63 (s, 3H). Mass spectrum (MS) (M+H)+: 230/232.

1190128-69-8
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75-16-1
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1256811-02-5
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Yield:1256811-02-5 71%

Reaction Conditions:

Stage #1: 5-bromo-N,2-dimethoxy-N-methylnicotinamide;methylmagnesium bromide in tetrahydrofuran at -78 - 20;
Stage #2: with ammonium chloride in tetrahydrofuran;

Steps:

47.3 Step 3 - Synthesis of l-(5-brom -2-methoxypyridin-3-yl)ethanone

To a solution of 5-bromo-N,2-dimethoxy-N-methylnicotinamide (5.0 g, 18.18 mmol) in THF (50 mL), MeMgBr (10 mL, 30.0 mmol) was added dropwise at -78 °C. The reaction mixture was stirred at 20 °C overnight. Then the reaction mixture was added to H4C1 solution. The mixture was extracted with EtOAc. The combined organic phases were washed with brine, dried over Na2S04, filtered and concentrated in vacuo. The crude product was purified using column chromatography (eluted with petroleum ether : EtOAc = 10 : 1) to provide l-(5-bromo-2-methoxypyridin-3-yl)ethanone (3.0 g, yield: 71%). 1H- MR (CDC13, 400 MHz) δ 8.33 (d, J= 2.4 Hz, 1H), 8.19 (d, J= 2.4 Hz, 1H), 4.03 (s, 3H), 2.63 (s, 3H). MS (M+H)+: 230 / 232

References:

WO2013/33971,2013,A1 Location in patent:Page/Page column 145

13472-60-1 Synthesis