Carbon Dioxide → 2-Methyl-1-benzothiophene-7-carboxylic acid

HRID 445805Notes

Reaction equation

HRID 445805 reaction equation
Br[C:2]1[C:7]2[S:8][C:9]([CH3:11])=[CH:10][C:6]=2[CH:5]=[CH:4][CH:3]=1.C([Li])CCC.[C:17](=[O:19])=[O:18]>O1CCCC1.C(OCC)C>[CH3:11][C:9]1[S:8][C:7]2[C:2]([C:17]([OH:19])=[O:18])=[CH:3][CH:4]=[CH:5][C:6]=2[CH:10]=1

Participants

6

Reactant 3

HCID 280Carbon DioxideHCID 126238737-Bromo-2-methyl-1-benzothiopheneHCID 178418339Butyllithium

Product 1

HCID 126239032-Methyl-1-benzothiophene-7-carboxylic acidYield 31.2%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

The solution of 7-bromo-2-methylbenzo[b]thiophene (508) (0.908 g, 4.0 mmol) in tetrahydrofuran (16 mL) was cooled to −78° C. under nitrogen. n-butyllithium (2.40 mL, 6.0 mmol, 1.0M in Hexanes) was added dropwise. After the addition was complete, the reaction mixture was stirred at −78° C. for 1 h, then poured on to the mixture of dry ice in ethyl ether (30 mL). The reaction was stirred to reach room temperature for 5 hours, followed by washing with 1N HCl, brine and dried over sodium sulfate, filtered, and concentrated in vacuo. The obtained white solid was washed with hexanes to provide 2-methylbenzo[b]thiophene-7-carboxylic acid (509) (0.240 g, 31.2%). LC-MS ESI m/z: found 191.0 [M−H]−.

Workup

  1. additionAfter the addition
  2. stirringThe reaction was stirred
  3. waitto reach room temperature for 5 hours
  4. washby washing with 1N HCl, brine
  5. dry with materialdried over sodium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated in vacuo
  8. washThe obtained white solid was washed with hexanes

Sources & evidence

ORD record
ord-b7e12646e8554786b960c13c25d67d93
Source dataset
uspto-grants-2013_07
Patent number
US08476308B2

Reaction notes

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