Sulfuric Acid → 2,3-Dichloro-4-methoxybenzene-1-thiol

HRID 370967Notes

Reaction equation

HRID 370967 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](Cl)(=O)=O.S(=O)(=O)(O)O>ClCCl.[Zn]>[Cl:1][C:2]1[C:7]([Cl:8])=[C:6]([O:9][CH3:10])[CH:5]=[CH:4][C:3]=1[SH:11]

Participants

5

Reactant 2

HCID 1118Sulfuric AcidHCID 159142682,3-Dichloro-4-methoxybenzene-1-sulfonyl chloride

Product 1

HCID 159142692,3-Dichloro-4-methoxybenzene-1-thiolYield 77.4%

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 6344DichloromethaneSolvent

Procedure

A mixture of 9.37 g of 2,3-dichloro-4-methoxybenzenesulfonyl chloride, 72 g of crushed ice, 24 g of conc. sulfuric acid and 12 g of zinc dust is stirred under reflux for 16 hours. The mixture is diluted with dichloromethane, cooled and stirred at room temperature for 2 hours. Filtration removes the unreacted zinc and the organic extracts are washed with water, sodium bicarbonate solution and dried over anhydrous magnesium sulfate. Removal of solvent in vacuo leaves a white solid which is recrystallized from ether-pentane to give 5.5 g of 2,3-dichloro-4-methoxy-thiophenol as colorless needles, mp 81.5°-83°.

Workup

  1. temperatureunder reflux for 16 hours
  2. temperaturecooled
  3. stirringstirred at room temperature for 2 hours
  4. filtrationFiltration
  5. customremoves the unreacted zinc
  6. washthe organic extracts are washed with water, sodium bicarbonate solution
  7. dry with materialdried over anhydrous magnesium sulfate
  8. customRemoval of solvent in vacuo
  9. customleaves a white solid which
  10. customis recrystallized from ether-pentane

Sources & evidence

ORD record
ord-da599bf63eb548538e475c168cea25c8
Source dataset
uspto-grants-1985_07
Patent number
US04528399

Reaction notes

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