Boron → 6,7-Dichloro-5-methoxy-2-n-propylbenzo[b]thiophene

HRID 371005Notes

Reaction equation

HRID 371005 reaction equation
[Cl:1][C:2]1[C:3]([O:16][CH3:17])=[CH:4][C:5]2[CH:9](O)[CH:8]([CH2:11][CH2:12][CH3:13])[S:7][C:6]=2[C:14]=1[Cl:15].[B]>C(O)(=O)C>[Cl:1][C:2]1[C:3]([O:16][CH3:17])=[CH:4][C:5]2[CH:9]=[C:8]([CH2:11][CH2:12][CH3:13])[S:7][C:6]=2[C:14]=1[Cl:15]

Participants

4

Reactant 2

HCID 5462311BoronHCID 13290182HCID 13290182, compound

Product 1

HCID 139528716,7-Dichloro-5-methoxy-2-n-propylbenzo[b]thiopheneYield 75.1%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To a mixture of 44 g of 6,7-dichloro-2,3-dihydro-3-hydroxy-5-methoxy-2-n-propylbenzo[b]thiophene in 275 ml of glacial acetic acid is added 65 ml of boron triluoride etherate and the mixture is warmed on a steam bath until it becomes clear. The solution is stired for 10 mins and then quenched with a mixture of 500 g of ice and 200 ml of a 10% sodium hydroxide solution. The mixture is neutralized with 50% sodium hydroxide solution and then extracted with two 300-ml portions of ethyl ether. The organic layers are combined, washed with 100 ml of a saturated sodium bicarbonate solution, 100 ml of water, dried over anhydrous magnesium sulfate, filtered and the solvent is removed to give an oil. Chromatography of the oil on an alumina column using 9:1-hexane:ethyl ether as eluting solvent gives 31 g of 6,7-dichloro-5-methoxy-2-n-propylbenzo[b]thiophene as an oil.

Workup

  1. temperaturethe mixture is warmed on a steam bath until it
  2. customquenched with a mixture of 500 g of ice and 200 ml of a 10% sodium hydroxide solution
  3. extractionextracted with two 300-ml portions of ethyl ether
  4. washwashed with 100 ml of a saturated sodium bicarbonate solution, 100 ml of water
  5. dry with materialdried over anhydrous magnesium sulfate
  6. filtrationfiltered
  7. customthe solvent is removed
  8. customto give an oil
  9. wash1-hexane:ethyl ether as eluting solvent

Sources & evidence

ORD record
ord-623363c524ab463781b86bc90db63f16
Source dataset
uspto-grants-1985_07
Patent number
US04528399

Reaction notes

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