Phosphorus oxychloride → 3-Bromo-2,5-dichloropyridine

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-bromo-5-chloropyridin-2-one (84.3 g, 0.404 tool) in DMF (100 mL) was added POCl3 (56.5 mL, 0.61 tool) via dropping funnel over 3 hours at room temperature. The resulting black solution was then heated to 70° C. and allowed to stir for 3 days. After cooling to room temperature, the solution was poured into 1L of ice/water, filtered, and the solid dried in a vacuum oven to provide 81.76 g (89%) of the desired 3-bromo-2, 5-dichloropyridine as an off-white solid, m.p. 39°-41° C.: IR(CHCl3) 3867, 3663, 2989, 2734, 1812, 1606, 1547, 1400, 1366, 1230, 1155, 1129, 1074, 1027, 894, 658, 563cm ; HNMR (300 MHz, CDCl3)δ 8.0 (d, 1H, J=2.2Hz) , 8.35 (d, 1H, J=2.2Hz); 13C NMR (CDCl3)δ 120.43, 130.74, 141.46, 146.64, 148.99; exact mass calculated for C5H2NBrCl2 =224.8748; high resolution mass spec. 224.8764.

Provenance & Evidence