Reacción #356117

Ecuación de reacción

2-bromo-3-hydroxypyridine

Tf2O

→

title compound

Rendimiento 94.0%

Trifluoro-methanesulfonic acid 2-bromo-pyridin-3-yl ester

Rendimiento 94.0%

Disolventes

pyridine

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroat −10° C.
2. 2
   Otrothe temperature below −5° C. (30 min)
3. 3
   OtroThe cooling bath was removed
4. 4
   Otroto reach 23° C.
5. 5
   workup.ADDITIONpoured into sat. NaHCO3-sol
6. 6
   Extracción, extracted with DCM
7. 7
   Lavadowashed with brine
8. 8
   Secadodried over Na2SO4
9. 9
   OtroRemoval of the solvent in vacuum
10. 10
    workup.WAITleft a brown oil, which
11. 11
    workup.DISTILLATIONwas purified by vacuum distillation
12. 12
    Otrotriturated with hexane
13. 13
    Filtraciónfiltered the undesired solid off,
14. 14
    Lavadowashed with hexane
15. 15
    Otrocollected the mother liquor
16. 16
    Otroevaporated the solvent

Procedimiento

To a solution of 2-bromo-3-hydroxypyridine [CAS 6602-32-0, commercially available] (25.0 g, 144 mmol) in anhydrous pyridine (145 mL) at −10° C. (ice/NaCl) was drop wise added Tf2O (24.2 mL, 147 mmol) keeping the temperature below −5° C. (30 min). The cooling bath was removed and mixture was allowed to reach 23° C., stirred at 23° C. for 75 min, poured into sat. NaHCO3-sol., extracted with DCM, washed with brine, dried over Na2SO4. Removal of the solvent in vacuum left a brown oil, which was purified by vacuum distillation: bp 65° C. (0.82 mbar) (42 g colorless oil, with some solid); triturated with hexane, filtered the undesired solid off, washed with hexane, collected the mother liquor, evaporated the solvent to give the title compound as a colorless liquid (41.52 g, 94%). MS (TOF ESP) 306 [(M+H)+], 307.85 [(M+2+H)+].

Fuente