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ChemicalBook CAS DataBase List 3-Bromo-5-methoxypyridine
50720-12-2

3-Bromo-5-methoxypyridine synthesis

5synthesis methods
3,5-Dibromopyridine

625-92-3

3-Bromo-5-methoxypyridine

50720-12-2

Example 7A Synthesis of 3-bromo-5-methoxypyridine: Methanol (180 mL) was treated batchwise with sodium pellets (4.7 g, 0.20 mol) under dry conditions and subsequently evaporated to dryness. The residue was azeotroped with toluene (100 mL) and then concentrated under reduced pressure to completely remove water. To dry DMF (130 mL), the sodium methanol solution prepared above was added, followed by 3,5-dibromopyridine (32 g, 135 mmol, purchased from Avocado Chemicals). The reaction mixture was heated at 70 °C for 4 hours. After completion of the reaction, the mixture was slowly poured into an ice/water mixture (300 g) and the precipitate was collected by filtration. The filter cake was dried under reduced pressure to give the target product 3-bromo-5-methoxypyridine (15.6 g, 62% yield). Mass spectrometry analysis (DCI/NH3) showed m/z 188/190 (M + H)+, confirming the product structure.

-

Yield:50720-12-2 73%

Reaction Conditions:

with sodium hydride in N,N-dimethyl-formamide;mineral oil at 20 - 90; for 1 h;

Steps:

j00643j 3-Bromo-5-methoxypyridine (2):
1006441 A suspension of 60% sodium hydride (11.4 g, 285 mmol) in DMF (450 mL) was charged with methanol (11.5 mL, 285 mmol) at room temperature and heated to 60°C. The resulting solution was charged with 3,5-dibromopyridine (45 g, 190 mmol) and heated to 90°Cfor 1 h. The reaction mixture was cooled to room temperature, diluted with water (50 mL) and extracted with diethyl ether (3 X 50 mL). The combined organic layers were washed with brine, dried over anhydrous Na2504, filtered and concentrated in vacuo resulting in crude compound which was purified by chromatography on silica gel, eluting with 5-10% ethyl acetate in hexane to give 26.1 g, 73% yield of the title compound as an off white solid. ‘H NMR (400 MHz, CDC13): ? = 8.27 (d, J= 17.20 Hz, 2 H), 7.36 (s, 1 H), 3.86 (br. s, 3 H); MS (E5): m/z = 187.85 [M-Hf; LCMS: tR = 1.81 mm.

References:

COFERON, INC.;FOREMAN, Kenneth, W.;JIN, Meizhong;WANNER, Jutta;WERNER, Douglas, S. WO2015/106292, 2015, A1 Location in patent:Paragraph 00634; 00643; 00644

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