Dimethylformamide → 3-Bromo-5-phenoxypyridine

Temperature

110 °C

Sodium phenoxide trihydrate (7.50 g, 44.1 mmol) was dried under vacuum at 65° C. for 18 h at 0.6 mm Hg to yield 5.08 g of sodium phenoxide. Under a nitrogen atmosphere, 3,5-dibromopyridine (4.00 g, 16.9 mmol) and anhydrous N,N-dimethylformamide (40 mL) were added to the sodium phenoxide (5.08 g, 43.8 mmol). The resulting mixture was stirred at 110° C. for 44 h. After cooling to ambient temperature, water (75 mL) was added, and the pH was adjusted to 13.0 using 30% NaOH solution. The solution was extracted with diethyl ether (4×60 mL). The combined ether extracts were washed with saturated NaCl solution (50 mL), dried (NaSO4), filtered and concentrated by rotary evaporation to a brown oil (4.0 g). The oil was vacuum distilled, collecting a forerun (317 mg), bp 48-65° C. at 0.05 mm Hg. Further distillation afforded 3.35 g (79.8%) of 3-bromo-5-phenoxypyridine as a pale-yellow oil, bp 75-112° C. at 0.05 mm Hg (lit. bp 110-115° C. at 1.7 mm Hg, see K. Fujikawa, et al. Agr. Biol. Chem. 34:68 (1970).

1. temperatureAfter cooling to ambient temperature
2. extractionThe solution was extracted with diethyl ether (4×60 mL)
3. washThe combined ether extracts were washed with saturated NaCl solution (50 mL)
4. dry with materialdried (NaSO4)
5. filtrationfiltered
6. concentrationconcentrated by rotary evaporation to a brown oil (4.0 g)
7. distillationdistilled
8. customcollecting a forerun (317 mg), bp 48-65° C. at 0.05 mm Hg
9. distillationFurther distillation

ORD record

ord-63e02146bdad461ca3da6e0fdab08279

Source dataset

uspto-grants-2003_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06531606B1