Phosphorus pentachloride → 6-Chloro-8-methyl-3,4-dihydro-2H-1-benzopyran-4-one

HRID 1385992Notes

Reaction equation

HRID 1385992 reaction equation
P(Cl)(Cl)(Cl)(Cl)Cl.[Cl:7][C:8]1[CH:19]=[CH:18][C:11]([O:12][CH2:13][CH2:14][C:15]([OH:17])=O)=[C:10]([CH3:20])[CH:9]=1.[Cl-].[Al+3].[Cl-].[Cl-]>C1C=CC=CC=1>[Cl:7][C:8]1[CH:19]=[C:18]2[C:11](=[C:10]([CH3:20])[CH:9]=1)[O:12][CH2:13][CH2:14][C:15]2=[O:17]

Participants

5

Reactant 3

HCID 24819Phosphorus pentachlorideHCID 619053-(4-Chloro-2-methylphenoxy)propionic acidHCID 6451240Aluminum(III) Chloride

Product 1

HCID 139538296-Chloro-8-methyl-3,4-dihydro-2H-1-benzopyran-4-oneYield 50.9%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

Phosphorous pentachloride (0.95 g, 4.6 mmol) was added to a suspension of 3-(4-chloro-2-methylphenoxy)propionic acid (0.59 g; 2.7 mmol; from step (ii) above) in benzene (10 mL). The resultant clear solution was heated quickly to boiling and then cooled on an ice bath. Aluminium chloride (1.0 g; 7.5 mmol) was added in portions and, after complete addition, ice water was added. Extraction with ether, washing of the organic layer with NaHCO3/aq. and NaOH (2M; aq.), drying (Na2SO4) and concentration yielded 0.27 g (50%) of the sub-title compound.

Workup

  1. temperatureThe resultant clear solution was heated quickly
  2. temperaturecooled on an ice bath
  3. additionwas added
  4. extractionExtraction with ether
  5. washwashing of the organic layer with NaHCO3/aq
  6. dry with materialand NaOH (2M; aq.), drying
  7. concentration(Na2SO4) and concentration

Sources & evidence

ORD record
ord-b43bce89d14141b5a3af5ec253411d6e
Source dataset
uspto-grants-2001_07
Patent number
US06265397B1

Reaction notes

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