1,4-Dibromobenzene → HCID 70097928, compound

HRID 840527Notes

Reaction equation

HRID 840527 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][CH:3]=1.CC(C)=O.C(=O)=O.[Li]CCCC.[CH3:21][Si:22](Cl)([CH3:35])[CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH3:34]>C1COCC1.O>[Br:8][C:5]1[CH:6]=[CH:7][C:2]([Si:22]([CH3:21])([CH3:35])[CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH3:34])=[CH:3][CH:4]=1

Participants

7

Reactant 4

HCID 78041,4-DibromobenzeneHCID 2758731Chloro(dodecyl)dimethylsilaneHCID 18522661Acetone cardiceHCID 178418339Butyllithium2×

Product 1

HCID 70097928HCID 70097928, compoundYield 90%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-78 °C

Procedure

100 mL of THF and 8.5 g (0.036 moles) of 1,4-dibromobenzene were put into a Schlenk flask which had been filled with nitrogen. Then the flask was agitated. The temperature was maintained at −78° C. by using acetone/dry ice. 22.6 mL (0.036 moles) of n-BuLi (1.6 M n-hexane solution) was slowly dropped into the reaction mixture over 10 minutes. After several minutes, a white salt began to be formed. After completion of the dropping of n-BuLi, a further agitation was carried out for about one hour. Then 10 g of dimethyldodecylsilyl chloride dissolved in 20 mL of THF was slowly dropped into the solution. Then the solution became clearer. After about three hours, the solution was put into 300 nL of water, and extracted with ethyl acetate. The extracts were dried by using anhydrous MgSO4 and filtered with a solvent, and then the solvent was evaporated. The obtained oil was either distilled in a vacuum (boiling point of 160-170° C./1.5 mmHg), or purified by a silica gel chromatography (eluent: n-hexane). Thus, 1-bromo-4-(dimethyldodecylsilyl)benzene (I) was obtained with a yield of about 90 % or above. The chemical structure of compound (I) was identified through 1H-NMR as follow: 1H-NMR (CDCl3): δ0.24 (s, 6H, Si(CH3)2), 0.72 (t, 2H, SiCH2), 0.89 (t, 3H,—CH3), 1.27 (m, 20H, (CH2)10, 7.37 and 7.49 (d, 4H, aromatic protons).

Workup

  1. additionwhich had been filled with nitrogen
  2. waitAfter several minutes
  3. customto be formed
  4. additionwas slowly dropped into the solution
  5. extractionextracted with ethyl acetate
  6. customThe extracts were dried
  7. filtrationfiltered with a solvent
  8. customthe solvent was evaporated
  9. distillationeither distilled in a vacuum (boiling point of 160-170° C./1.5 mmHg)
  10. custompurified by a silica gel chromatography (eluent: n-hexane)

Sources & evidence

ORD record
ord-9eba9b178c164f0599ae8d78c75281e1
Source dataset
uspto-grants-2002_04
Patent number
US06368732B1

Reaction notes

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