2-Bromo-3-pyridinol → 2-Bromo-3-pyridyl trifluoromethanesulfonate

Temperature

23 °C

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)+].

1. customat −10° C.
2. customthe temperature below −5° C. (30 min)
3. customThe cooling bath was removed
4. customto reach 23° C.
5. additionpoured into sat. NaHCO3-sol
6. extraction, extracted with DCM
7. washwashed with brine
8. dry with materialdried over Na2SO4
9. customRemoval of the solvent in vacuum
10. waitleft a brown oil, which
11. distillationwas purified by vacuum distillation
12. customtriturated with hexane
13. filtrationfiltered the undesired solid off,
14. washwashed with hexane
15. customcollected the mother liquor
16. customevaporated the solvent

ORD record

ord-fca51cbe944044349ec0389343083d7f

Source dataset

uspto-grants-2008_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07446113B2