ChemicalBook CAS DataBase List 3-Bromo-2,6-difluoropyridine

3-Bromo-2,6-difluoropyridine synthesis

5synthesis methods

Product Name:3-Bromo-2,6-difluoropyridine
CAS Number:80392-79-6
Molecular formula:C5H2BrF2N
Molecular Weight:193.98

866755-20-6

80392-79-6

GENERAL METHOD: To a solution of 2,6-dichloro-3-bromopyridine (4.70 g, 20.7 mmol) in dimethyl sulfoxide (DMSO, 103 mL) was added cesium fluoride (12.6 g, 82.9 mmol) at room temperature. The reaction mixture was stirred in air at 80 °C for 8 hours. After completion of the reaction, the mixture was poured into room temperature water and extracted with ether (Et2O). The organic layer was separated, washed sequentially with water and saturated saline, dried over anhydrous sodium sulfate (Na2SO4) and subsequently concentrated under reduced pressure (400 Torr, 40°C). Purification of the residue by column chromatography (silica gel, hexane solution of ethyl acetate as eluent) afforded 3-bromo-2,6-difluoropyridine (2.58 g, 64% yield) as a colorless oil.1H NMR (CDCl3) δ: 6.79 (1H, dd, J = 8.3, 3.0 Hz), 8.03 (1H, ddd, J = 8.4, 8.4, 7.0 Hz).19F NMR (CDCl3) δ: -69.3 Hz, -63.8 Hz.Compounds 4B-8B were prepared according to the method similar to 3B.

866755-20-6
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80392-79-6
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Yield: 64%

Reaction Conditions:

with cesium fluoride in dimethyl sulfoxide at 80; for 8 h;

Steps:

3-Bromo-2,6-difluoropyridine(3B)
General procedure: To asolution of 3-bromo-2,6-dichloropyridine (4.70 g, 20.7 mmol) in DMSO (103 ml)was added cesium fluoride (12.6 g, 82.9 mmol) at room temperature. The mixturewas stirred at 80 °C under air for 8 h. The mixture was poured into water atroom temperature and extracted with Et₂O. The organic layer wasseparated, washed with water and brine, dried over Na₂SO₄and concentrated in vacuo. (400 Torr, 40 °C). The residue was purified bycolumn chromatography (silica gel, eluted with EtOAc in hexane) to give 3-bromo-2,6-difluoropyridine (3B) (2.58 g, 64%) as colorless oil. ¹H NMR (CDCl₃)δ: 6.79 1H,dd, J = 8.3, 3.0 Hz), 8.03 (1H, ddd, J = 8.4, 8.4 7.0 Hz). ¹⁹F NMR(CDCl₃) δ: -69.3 Hz, -63.8 Hz. The compound 4B-8B were prepared in a manner similarto that described for 3B.

References:

Katoh, Taisuke;Tomata, Yoshihide;Tsukamoto, Tetsuya;Nakada, Yoshihisa [Tetrahedron Letters,2015,vol. 56,# 44,p. 6043 - 6046] Location in patent:supporting information