Ethylene → 6,8-Dichloro-2-tetralone

HRID 569663Notes

Reaction equation

HRID 569663 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[CH2:9][C:10](Cl)=[O:11].[Cl-].[Al+3].[Cl-].[Cl-].[CH2:17]=[CH2:18]>C(Cl)Cl>[Cl:8][C:6]1[CH:5]=[C:4]2[C:3](=[C:2]([Cl:1])[CH:7]=1)[CH2:9][C:10](=[O:11])[CH2:18][CH2:17]2

Participants

5

Reactant 3

HCID 6325EthyleneHCID 2758147(2,4-Dichlorophenyl)acetyl chlorideHCID 6451240Aluminum(III) Chloride

Product 1

HCID 36539736,8-Dichloro-2-tetralone

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

149.4 g of 2,4-dichlorophenylacetyl chloride dissolved in 200 ml of methylene chloride were added dropwise within 60 minutes to 115 g of aluminum chloride in 700 ml of methylene chloride while stirring at 0° to 5°. Thereafter, ethylene was introduced at between 0° and 5° during 30 minutes, whereupon the mixture was stirred further at room temperature for 1 hour and thereafter treated at between 0° and 5° with 300 ml of ice-water. The methylene chloride phase was washed, respectively, with 2N hydrochloric acid, with water, with saturated sodium bicarbonate solution and again with water. The aqueous phases were extracted with methylene chloride. The methylene chloride phases were combined, dried and evaporated. The residue was triturated with 100 ml of low-boiling petroleum ether, a further 250 ml of low-boiling petroleum ether were later added thereto and the mixture was left to stand in a refrigerator for 72 hours. The solid was filtered off and filtered over 600 g of silica gel (particle size 0.2-0.5 mm) while eluting with chloroform. There was obtained 6.8-dichloro-3,4-dihydro-2(1H)-naphthalenone which exhibits a melting point of 90°-92° after recrystallization from low-boiling petroleum ether at 0° to 5°.

Workup

  1. stirringwas stirred further at room temperature for 1 hour
  2. washThe methylene chloride phase was washed
  3. extractionThe aqueous phases were extracted with methylene chloride
  4. customdried
  5. customevaporated
  6. customThe residue was triturated with 100 ml of low-boiling petroleum ether
  7. additiona further 250 ml of low-boiling petroleum ether were later added
  8. waitthe mixture was left
  9. filtrationThe solid was filtered off
  10. filtrationfiltered over 600 g of silica gel (particle size 0.2-0.5 mm)
  11. washwhile eluting with chloroform

Sources & evidence

ORD record
ord-066a48b783a04ef9a8100776a319b425
Source dataset
uspto-grants-1988_03
Patent number
US04732979

Reaction notes

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