Carbon Dioxide → 2,3-Dihydro-1-benzofuran-7-carboxylic acid

HRID 844570Notes

Reaction equation

HRID 844570 reaction equation
CN(C)CCN(C)C.C([Li])CCC.[O:14]1[CH2:18][CH2:17][C:16]2[CH:19]=[CH:20][CH:21]=[CH:22][C:15]1=2.[C:23](=[O:25])=[O:24]>CCCCCC>[O:14]1[CH2:18][CH2:17][C:16]2[CH:19]=[CH:20][CH:21]=[C:22]([C:23]([OH:25])=[O:24])[C:15]1=2

Participants

6

Reactant 4

HCID 280Carbon DioxideHCID 8037N,N,N',N'-TetramethylethylenediamineHCID 10329DihydrobenzofuranHCID 178418339Butyllithium

Product 1

HCID 27950142,3-Dihydro-1-benzofuran-7-carboxylic acid

Reagents, catalysts & solvents 1

HCID 8058HexaneSolvent2×

Conditions

Temperature
0 °C

Procedure

N,N,N′,N′-Tetramethylethylenediamine (38 ml) was dissolved in hexane (300 ml), cooled in an ice-bath and n-butyllithium (100 ml of a 2.5M solution in hexane) added. The mixture was stirred at 0°C. for 15 minutes before adding 2,3-dihydrobenzo[b]furan (30 g) dropwise over 30 minutes. The mixture was allowed to warm to room temperature over 30 minutes, stirred at room temperature for a further 4 hours, poured onto an excess of solid carbon dioxide and left to stand for 3 days by which time the solvent had evaporated off. The residue was partitioned between ethyl acetate (1L) and 4N aqueous hydrochloric acid solution (240 ml), the layers separated and the aqueous layer extracted with ethyl acetate (500 ml). The organic extracts were combined, dried over anhydrous sodium sulphate and the solvent removed under reduced pressure. The residue was then triturated with diethyl ether to give 2,3-dihydrobenzo[b]furan-7-oic acid as a white solid (21 g).

Workup

  1. temperaturecooled in an ice-bath
  2. temperatureto warm to room temperature over 30 minutes
  3. stirringstirred at room temperature for a further 4 hours
  4. waitleft
  5. waitto stand for 3 days by which time
  6. customthe solvent had evaporated off
  7. customThe residue was partitioned between ethyl acetate (1L) and 4N aqueous hydrochloric acid solution (240 ml)
  8. customthe layers separated
  9. extractionthe aqueous layer extracted with ethyl acetate (500 ml)
  10. dry with materialdried over anhydrous sodium sulphate
  11. customthe solvent removed under reduced pressure
  12. customThe residue was then triturated with diethyl ether

Sources & evidence

ORD record
ord-bbf6beaa311842d8877aa96e216f0d56
Source dataset
uspto-grants-2002_04
Patent number
US06380396B1

Reaction notes

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