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

HRID 2106736Notes

Reaction equation

HRID 2106736 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 firstly 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 firstly filtered over silica gel (eluting agent hexane)
  8. distillationsubsequently distilled in a water-jet vacuum

Sources & evidence

ORD record
ord-aef518cb13674cb5afdb177c82fb975a
Source dataset
uspto-grants-1990_06
Patent number
US04931458

Reaction notes

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