Benzyl Bromide → 7-Phenylhept-5-ynoic acid

HRID 1995772Notes

Reaction equation

HRID 1995772 reaction equation
[C:1]([OH:8])(=[O:7])[CH2:2][CH2:3][CH2:4][C:5]#[CH:6].[H-].[Na+].[H][H].[CH2:13](Br)[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1>CN(C)C=O>[C:14]1([CH2:13][C:6]#[C:5][CH2:4][CH2:3][CH2:2][C:1]([OH:8])=[O:7])[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1

Participants

6

Reactant 4

HCID 7498Benzyl BromideHCID 24758Sodium hydrideHCID 1430365-Hexynoic acidHCID 178418361HCID 178418361, compound

Product 1

HCID 204880087-Phenylhept-5-ynoic acid

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
80 °C

Procedure

A solution of hex-5-ynoic acid (1 mmole) in dimethylformamide (50 ml) is treated with sodium hydride (2 mmole; 50% dispersion in oil) first at room temperature, then at 60° C. A copious evolution of hydrogen occurs. Then, the solution is cooled and benzyl bromide (1.5 mmole) is added. The reaction mixture is heated to 80° C. and maintained thereat until then layer chromatography indicates the consumption of all the hex-5-ynoic acid. After cooling, the solution is poured onto a 10% sodium hydroxide solution and extracted with ethyl ether to remove unreacted benzyl bromide. The aqueous layer is then acidified to pH2 with concentrated hydrochloric acid, and extracted with chloroform. Removal of the solvent from the chloroform layer affords a residue which is distilled under reduced pressure to give the desired title product, 7-phenylhept-5-ynoic acid.

Workup

  1. customat 60° C
  2. temperatureThen, the solution is cooled
  3. temperaturemaintained
  4. customthe consumption of all the hex-5-ynoic acid
  5. temperatureAfter cooling
  6. additionthe solution is poured onto a 10% sodium hydroxide solution
  7. extractionextracted with ethyl ether
  8. customto remove unreacted benzyl bromide
  9. extractionextracted with chloroform
  10. customRemoval of the solvent from the chloroform layer
  11. customaffords a residue which
  12. distillationis distilled under reduced pressure

Sources & evidence

ORD record
ord-b051adca8b074383b9e5cac03a6714f3
Source dataset
uspto-grants-1983_09
Patent number
US04405810

Reaction notes

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