Ammonium Chloride → 3,5-Dibromostyrene

HRID 2380751Notes

Reaction equation

HRID 2380751 reaction equation
[CH3:1]C(C)([O-])C.[K+].[Br:7][C:8]1[CH:9]=[C:10]([CH:13]=[C:14]([Br:16])[CH:15]=1)[CH:11]=O.[Cl-].[NH4+]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.O1CCCC1>[Br:7][C:8]1[CH:9]=[C:10]([CH:13]=[C:14]([Br:16])[CH:15]=1)[CH:11]=[CH2:1]

Participants

6

Reactant 3

HCID 25517Ammonium ChlorideHCID 6220773,5-DibromobenzaldehydeHCID 23665647Potassium tert-butoxide

Product 1

HCID 186903433,5-DibromostyreneYield 79.3%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 8028TetrahydrofuranSolvent2×

Procedure

Tetrahydrofuran (20 mL) was added to methyltriphenylphosphonium bromide (3.150 g, 8.8 mmol). Then potassium t-butoxide (0.989 g, 8.8 mmol) was added herein small portions with ice-cooling, and the mixture was stirred at room temperature for 1 hr. The resultant slurry was cooled to −78° C. and a tetrahydrofuran (20 mL) solution containing 3,5-dibromobenzaldehyde (1.519 g, 5.8 mmol) was added dropwise. The reaction solution was allowed to warm to room temperature and stirred for 1 hr, and then a saturated ammonium chloride aqueous solution was added to the reaction solution. The product was extracted with ethyl acetate, the solvent was distilled off under reduced pressure, and the residue was purified with silica-gel column chromatography to obtain 3,5-dibromostyrene (1.2 g, 4.6 mmol).

Workup

  1. temperaturecooling
  2. temperatureThe resultant slurry was cooled to −78° C.
  3. additionwas added dropwise
  4. temperatureto warm to room temperature
  5. stirringstirred for 1 hr
  6. extractionThe product was extracted with ethyl acetate
  7. distillationthe solvent was distilled off under reduced pressure
  8. customthe residue was purified with silica-gel column chromatography

Sources & evidence

ORD record
ord-d1ff980968f943d1a2170927d015c4c1
Source dataset
uspto-grants-2012_09
Patent number
US08257837B2

Reaction notes

Loading…