Thionyl Chloride → 6,7-dichloro-5-methoxy-2-isopropylbenzo[b]thiophen-3(2H)-one

HRID 370965Notes

Reaction equation

HRID 370965 reaction equation
[Cl:1][C:2]1[C:7]([Cl:8])=[C:6]([O:9][CH3:10])[CH:5]=[CH:4][C:3]=1[S:11][CH:12]([CH:16]([CH3:18])[CH3:17])[C:13]([OH:15])=O.S(Cl)(Cl)=O>ClCCl>[Cl:8][C:7]1[C:6]([O:9][CH3:10])=[CH:5][C:4]2[C:13](=[O:15])[CH:12]([CH:16]([CH3:18])[CH3:17])[S:11][C:3]=2[C:2]=1[Cl:1]

Participants

4

Reactant 2

HCID 24386Thionyl ChlorideHCID 159142702-[(2,3-Dichloro-4-methoxyphenyl)sulfanyl]-3-methylbutanoic acid

Product 1

HCID 201979356,7-dichloro-5-methoxy-2-isopropylbenzo[b]thiophen-3(2H)-oneYield 45%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To 6.0 g of α-(2,3-dichloro-4-methoxyphenylthio)isovaleric acid in 27 ml of dry dichloromethane is added 5.5 ml of thionyl chloride. The reaction is heated under reflux for 1 hour and excess reagent is removed under aspirator pressure. The residue is diluted with 70 ml of dichloromethane and the resulting slurry is added over less than one minute to a slurry of 2.79 g of aluminum chloride in 8 ml of dichloromethane at -60°. The cooling bath is removed and the reaction allowed to warm to room temperature over one hour. Stirring is continued for an additional hour and reaction is quenched with 250 ml of water. The mixture is extracted with three 125 ml portions of ether and the combined ether extracts are washed with two 150 ml portions and one 60 ml portion of saturated sodium bicarbonate solution, water and brine and dried over anhydrous magnesium sulfate to give 2.54 g of oily 6,7-dichloro-5-methoxy-2-isopropylbenzo[b]thiophen-3(2H)-one.

Workup

  1. temperatureThe reaction is heated
  2. temperatureunder reflux for 1 hour
  3. customexcess reagent is removed under aspirator pressure
  4. additionThe residue is diluted with 70 ml of dichloromethane
  5. additionthe resulting slurry is added over less than one minute to a slurry of 2.79 g of aluminum chloride in 8 ml of dichloromethane at -60°
  6. customThe cooling bath is removed
  7. waitis continued for an additional hour
  8. customreaction
  9. customis quenched with 250 ml of water
  10. extractionThe mixture is extracted with three 125 ml portions of ether
  11. washthe combined ether extracts are washed with two 150 ml portions and one 60 ml portion of saturated sodium bicarbonate solution, water and brine
  12. dry with materialdried over anhydrous magnesium sulfate

Sources & evidence

ORD record
ord-e0f851245f324d49b56c429140a67058
Source dataset
uspto-grants-1985_07
Patent number
US04528399

Reaction notes

Loading…