Imidazole → (3-Bromo-4-methylphenoxy)(tert-butyl)dimethylsilane

HRID 1735385Notes

Reaction equation

HRID 1735385 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([OH:9])[CH:5]=[CH:6][C:7]=1[CH3:8].[Cl-].[Al+3].[Cl-].[Cl-].[C:14]([Si:18]([CH3:21])([CH3:20])Cl)([CH3:17])([CH3:16])[CH3:15].N1C=CN=C1>CN(C)C=O>[Br:1][C:2]1[CH:3]=[C:4]([O:9][Si:18]([C:14]([CH3:17])([CH3:16])[CH3:15])([CH3:21])[CH3:20])[CH:5]=[CH:6][C:7]=1[CH3:8]

Participants

6

Reactant 4

HCID 795ImidazoleHCID 28928tert-Butyldimethylsilyl chlorideHCID 6451240Aluminum(III) ChlorideHCID 103079133-Bromo-4-methylphenol

Product 1

HCID 19437122(3-Bromo-4-methylphenoxy)(tert-butyl)dimethylsilaneYield 54.5%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

3-Bromo-4-methylphenol(25.0 g, 0.134 mol) and aluminum chloride (36.11 g, 0.27 mol) were heated to 127° C. for 2 h. Ice was added, the solution extracted with ethyl acetate, dried (Na2SO4) and evaporated to dryness under reduced pressure. N,N-Dimethyl formamide (150 ml), t-butyl-dimethylchlorosilane (25.0 g, 165 mmol) and imidazole (22.6 g, 33.2 mmol) were added and the solution stirred at room temperature for 16 h. The products were partitioned between water and ethyl acetate, the organic layer separated, dried (Na2SO4) and evaporated to dryness under reduced pressure. Purification by flash chromatography using hexane as eluent gave impure 1-bromo-2-methyl-5-t-butyldimethylsilyloxybenzene (22.0 g). Carbon tetrachloride (125 ml) and N-bromosuccinimide (10.80 g, 66.6 mmol) were added and the solution heated to reflux over a 150 W light bulb for 2 h. The solution was cooled to 5° C., filtered and evaporated to dryness under reduced pressure. Purification by flash chromatography using hexane as eluent gave the title compound (12.64 g, 21%) as a white solid; δH (CDCl3) 0.21 (6H, s, Si(CH3)2), 0.97 (9H, s, t-Bu), 4.59 (2H, s, CH2Br), 6.76 (1H, dd, J 8.3 and 2.4 Hz, 4-H), 7.07 (1H, d, J 2.4 Hz, 6-H), 7.30 (1H, d, J 8.4 Hz, 3-H): m/z (E.I.) 382 (M+, 2%), 380 (M+, 4%), 378 (M+, 2%), 299 (100%): (Found: M-, 377.9647). C13H20OBr2Si requires M, 377.9650).

Workup

  1. additionIce was added
  2. extractionthe solution extracted with ethyl acetate
  3. dry with materialdried (Na2SO4)
  4. customevaporated to dryness under reduced pressure
  5. customThe products were partitioned between water and ethyl acetate
  6. customthe organic layer separated
  7. dry with materialdried (Na2SO4)
  8. customevaporated to dryness under reduced pressure
  9. customPurification by flash chromatography

Sources & evidence

ORD record
ord-c1e2ee51ea9f420da99cd29ca53909fc
Source dataset
uspto-grants-1996_07
Patent number
US05536745

Reaction notes

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