Imidazole → (4-Bromophenoxy)(tert-butyl)dimethylsilane

HRID 2068170Notes

Reaction equation

HRID 2068170 reaction equation
[CH:1]1[C:6]([OH:7])=[CH:5][CH:4]=[C:3]([Br:8])[CH:2]=1.N1C=CN=C1.[Si:14](Cl)([C:17]([CH3:20])([CH3:19])[CH3:18])([CH3:16])[CH3:15].[NH4+].[Cl-]>ClCCCl>[Br:8][C:3]1[CH:4]=[CH:5][C:6]([O:7][Si:14]([C:17]([CH3:20])([CH3:19])[CH3:18])([CH3:16])[CH3:15])=[CH:1][CH:2]=1

Participants

6

Reactant 4

HCID 795ImidazoleHCID 78084-BromophenolHCID 25517Ammonium ChlorideHCID 28928tert-Butyldimethylsilyl chloride

Product 1

HCID 4227167(4-Bromophenoxy)(tert-butyl)dimethylsilaneYield 99.6%

Reagents, catalysts & solvents 1

HCID 111,2-DichloroethaneSolvent

Procedure

To a stirred solution of p-bromophenol (30 g, 0.1734 mol) in 1,2-dichloroethane (300 mL) at 23° C. was added imidazole (29.45 g, 0.433 mol). After 15 min, tert-butyldimethylsilylchloride (28.75 g, 0.190 mol) was added, and the resulting solution heated at reflux for 3 h. The mixture was cooled to room temperature and poured onto saturated aqueous NH4Cl and extracted with CH2Cl2 (3×200 mL). The combined extracts were washed with brine (200 mL), dried (NaSO4), filtered and evaporated in vacuo. The crude product was distilled via short-path distillation (0.5 mm Hg, 130° C.) to give (4-bromo-phenoxy)-tert-butyl-dimethylsilane (49.6 g, 99.5% yield) as a colorless oil. Rf=0.80 (1:3 EtOAc/hexanes). IR (thin film) 3390, 2951, 2928, 1584, 1479, 1250 cm−1. 1H NMR (300 MHz, CDCl3) δ 7.34 (1H, d, J=9 Hz), 6.74 (1H, d, J=9 Hz), 1.00 (12H, s), 0.21 (6H, s). 13C NMR (75 MHz, CDCl3) δ 154.76, 132.22, 121.83, 113.55, 25.58, 18.12, −4.54. HRMS calcd. for C12H20BrOSi (MH+) 287.0461. Found 287.0463.

Workup

  1. temperaturethe resulting solution heated
  2. temperatureat reflux for 3 h
  3. extractionextracted with CH2Cl2 (3×200 mL)
  4. washThe combined extracts were washed with brine (200 mL)
  5. dry with materialdried (NaSO4)
  6. filtrationfiltered
  7. customevaporated in vacuo
  8. distillationThe crude product was distilled via short-path distillation (0.5 mm Hg, 130° C.)

Sources & evidence

ORD record
ord-570222a583964363b8db7535fea0abd3
Source dataset
uspto-grants-2012_10
Patent number
US08293927B2

Reaction notes

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