Methanesulfonyl chloride → 2-Bromo-5-(methylsulfonyl)pyridine

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,5-dibromopyridine (50 g, 211 mmol) in tetrahydrofuran (175 mL) at 0° C. was added 2.0 M isopropylmagnesium chloride (274 mmol) at a rate which maintained the temperature below 8° C. The reaction mixture was stirred at 0° C. for 45 minutes, then cooled to −15° C. A solution of methanesulfonyl chloride (32.2 g, 281 mmol) in tetrahydrofuran (40 mL) was added to the reaction mixture at a rate which maintained the temperature below 5° C. The reaction mixture was allowed to warm to room temperature and then quenched with water (500 mL) and tert-butylethylether (300 mL). The layers were separated, the aqueous layer was extracted twice with tert-butylethylether (2×200 mL). The combined organic extracts were washed with water (200 mL) and concentrated. The crude product was crystallized from toluene (110 mL) and the solids were filtered to afford 29.4 g (59% yield) of 2-bromo-5-(methanesulfonyl)-pyridine. Analytical data: 1H NMR (300 MHz, CDCl3) δ 3.13 (s, 3H), 7.73 (d, J=8.3 Hz, 1H), 8.07 (dd, J1=8.3 Hz, J2=2.7 Hz, 1H), 8.91 (d, J=2.5 Hz, 1H).

Provenance & Evidence