Thiophene → 4,4,7,7-Tetramethyl-4,5,6,7-tetrahydro-1-benzothiophene

HRID 485030Notes

Reaction equation

HRID 485030 reaction equation
[CH3:1][C:2](Cl)([CH2:4][CH2:5][C:6]([CH3:9])(Cl)[CH3:7])[CH3:3].[S:11]1[CH:15]=[CH:14][CH:13]=[CH:12]1>CCCCCC.[Ti](Cl)(Cl)(Cl)Cl>[CH3:1][C:2]1([CH3:3])[C:13]2[CH:14]=[CH:15][S:11][C:12]=2[C:6]([CH3:9])([CH3:7])[CH2:5][CH2:4]1

Participants

5

Reactant 2

HCID 8030ThiopheneHCID 80360Hexane, 2,5-dichloro-2,5-dimethyl-

Product 1

HCID 184668514,4,7,7-Tetramethyl-4,5,6,7-tetrahydro-1-benzothiophene

Reagents, catalysts & solvents 2

HCID 24193Titanium TetrachlorideCatalystHCID 8058HexaneSolvent

Conditions

Temperature
40 °C

Procedure

90 g of 2,5-dimethyl-2,5-dichlorohexane and 195 ml of thiophene are dissolved in 400 ml of hexane. 54 ml of titanium tetrachloride are slowly added dropwise thereto while cooling with ice, the mixture is warmed to 40° C. for 1.5 hours, again cooled with ice and the dark red mixture is treated cautiously with ice-water. The mixture is extracted three times with ether, the organic phase is washed with saturated sodium bicarbonate solution, dried and evaporated. The thus-obtained black oil is firsly filtered over silica gel (eluting agent hexane) and subsequently distilled in a water-jet vacuum. There are obtained 18.5 g of 4,5,6,7-tetrahydro-4,4,7,7-tetramethylbenzo[b]thiophene as a colorless liquid, b.p. 95°-96° C./10 mm.

Workup

  1. temperaturewhile cooling with ice
  2. temperatureagain cooled with ice
  3. extractionThe mixture is extracted three times with ether
  4. washthe organic phase is washed with saturated sodium bicarbonate solution
  5. customdried
  6. customevaporated
  7. filtrationThe thus-obtained black oil is firsly filtered over silica gel (eluting agent hexane)
  8. distillationsubsequently distilled in a water-jet vacuum

Sources & evidence

ORD record
ord-f778d366c55c4d6b9cc831323f99d0f7
Source dataset
uspto-grants-1985_08
Patent number
US04535086

Reaction notes

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