Carbon Dioxide → 6-Methylbenzo[b]thiophene-3-carboxylic acid

HRID 648025Notes

Reaction equation

HRID 648025 reaction equation
C([Li])CCC.Br[C:7]1[C:8]2[CH:15]=[CH:14][C:13]([CH3:16])=[CH:12][C:9]=2[S:10][CH:11]=1.[C:17](=[O:19])=[O:18]>CCOCC>[CH3:16][C:13]1[CH:14]=[CH:15][C:8]2[C:7]([C:17]([OH:19])=[O:18])=[CH:11][S:10][C:9]=2[CH:12]=1

Participants

5

Reactant 3

HCID 280Carbon DioxideHCID 12398618HCID 12398618, compoundHCID 178418339Butyllithium

Product 1

HCID 136629696-Methylbenzo[b]thiophene-3-carboxylic acid

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Conditions

Temperature
-70 °C

Procedure

A solution of n-butyl lithium (15 ml. of 1.0 M solution in hexane) was added dropwise to a stirred solution of 3-bromo-6-methylbenzo[b]thiophene (3.0 g.) in dry ether (40 ml.) at -70° C. under an atmosphere of dry nitrogen. The mixture was stirred at -70° C. for 30 minutes and then an excess of crushed solid carbon dioxide was added. When all the carbon dioxide had evaporated, water (25 ml.) was added and the mixture was stirred for a few minutes. The organic layer was separated and washed with 2 N.NaOH solution. The aqueous layer and NaOH extract were combined and acidified with concentrated hydrochloric acid. The solid was filtered off, washed with water, dried and crystallized from toluene to give 6-methylbenzo[b]thiophene-3-carboxylic acid (1.60 g.), m.p. 205°-209°.

Workup

  1. customWhen all the carbon dioxide had evaporated
  2. additionwater (25 ml.) was added
  3. stirringthe mixture was stirred for a few minutes
  4. customThe organic layer was separated
  5. washwashed with 2 N
  6. extractionThe aqueous layer and NaOH extract
  7. filtrationThe solid was filtered off
  8. washwashed with water
  9. customdried
  10. customcrystallized from toluene

Sources & evidence

ORD record
ord-fd501ebc6967486aa6b431eefd7a8ec1
Source dataset
uspto-grants-1983_10
Patent number
US04410539

Reaction notes

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