Thionyl Chloride → trans 3-Bromocinnamoyl chloride

HRID 441556Notes

Reaction equation

HRID 441556 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([CH:10]=[CH:11][CH:12]=1)/[CH:5]=[CH:6]/[C:7](O)=[O:8].S(Cl)([Cl:15])=O>C1C=CC=CC=1>[Br:1][C:2]1[CH:3]=[C:4]([CH:10]=[CH:11][CH:12]=1)/[CH:5]=[CH:6]/[C:7]([Cl:15])=[O:8]

Participants

4

Reactant 2

HCID 24386Thionyl Chloride2×HCID 776461m-Bromocinnamic acid

Product 1

HCID 14959106trans 3-Bromocinnamoyl chlorideYield 99.8%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent2×

Procedure

Trans m-bromocinnamic acid (11.4 g) in dry benzene (75 ml) was heated to reflux and then a mixture of thionyl chloride (12 g) in dry benzene (50 ml) was added at such a rate as to maintain constant reflux. The reaction mixture was heated at reflux for an additional 2 hr. after the addition of thionyl chloride. The solvent and excess thionyl chloride were then removed under reduced pressure to give trans 3-bromocinnamoyl chloride (ca. 12.3 g). A solution of the 3-bromocinnamoyl chloride in toluene (150 ml) was added dropwise with stirring to a solution of isopropylamine (10 g) in ether (200 ml). The reaction mixture was stirred at room temperature for 1 hour and then heated at reflux for 1 hour. The solvent and excess amine were removed under reduced pressure. The crude residue was triturated with water, filtered, and recrystallized from ethanol-water to give white, crystalline trans 3-bromo-N-isopropylcinnamamide, m.p. 85°-86° C. Elemental analysis, NMR and IR spectra all confirmed the identity of the product.

Workup

  1. temperatureto reflux
  2. additionwas added at such a rate as
  3. temperatureto maintain constant reflux
  4. temperatureThe reaction mixture was heated
  5. temperatureat reflux for an additional 2 hr
  6. customThe solvent and excess thionyl chloride were then removed under reduced pressure

Sources & evidence

ORD record
ord-7e4aac4ca916414eb158c7dd6afb7aa0
Source dataset
uspto-grants-1977_08
Patent number
US04041071

Reaction notes

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