Phosphorus oxybromide → HCID 21106849, compound

HRID 1765123Notes

Reaction equation

HRID 1765123 reaction equation
[F:1][C:2]1[CH:14]=[CH:13][CH:12]=[C:11]([F:15])[C:3]=1[CH2:4][N:5]1[CH2:9][CH:8]=[CH:7][N:6]1O.P(Br)(Br)([Br:18])=O>C(Cl)(Cl)Cl>[Br:18][C:9]1[N:5]([CH2:4][C:3]2[C:2]([F:1])=[CH:14][CH:13]=[CH:12][C:11]=2[F:15])[N:6]=[CH:7][CH:8]=1

Participants

4

Reactant 2

HCID 24613Phosphorus oxybromideHCID 68709545HCID 68709545, compound

Product 1

HCID 21106849HCID 21106849, compoundYield 96.7%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent2×

Procedure

2-(2,6-Difluorobenzyl)-1-hydroxy-1H-pyrazole (81.2 mg, 0.386 mmol, 1.0 eq) and 5 ml of anhydrous CHCl3 were combined in a flame-dried 25 mL round-bottom flask under argon and cooled in an ice/water bath. A solution of POBr3 (398.1 mg, 1.39 mmol, 3.60 eq) in 3 mL of CHCl3 was added using a syringe in aliquots over an hour period with stirring. The reaction solution was warmed to room temperature and stirred for 16 hours. The CHCl3 was removed in vacuo and the resulting orange mixture was neutralized with saturated aqueous NaHCO3 and extracted with 3×30 mL of diethyl ether. The combined ether fractions were washed with brine, dried over Na2SO4 and concentrated in vacuo to yield 101.5 mg (96.7% yield) of 5-bromo-1-(2,6-difluorobenzyl)-1H-pyrazole as a hygroscopic orange-tan colored solid. 1H NMR (CDCl3 300 MHz) δ 7.51 (d, 1H), 7.34 (m, 1H), 6.94 (t, 2H), 6.29 (d, 1H), 5.50 (s, 2H). LC/MS (ES) M+1=273.1, 275.1

Workup

  1. temperaturecooled in an ice/water bath
  2. customover an hour
  3. stirringstirred for 16 hours
  4. customThe CHCl3 was removed in vacuo
  5. extractionextracted with 3×30 mL of diethyl ether
  6. washThe combined ether fractions were washed with brine
  7. dry with materialdried over Na2SO4
  8. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-106c3a35703c48dc8dca8a539439e47c
Source dataset
uspto-grants-2007_06
Patent number
US07226930B2

Reaction notes

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