Carbon Dioxide → 2,3-Dihydro-5-phenyl-4-benzofurancarboxylic acid

HRID 617411Notes

Reaction equation

HRID 617411 reaction equation
I[C:2]1[C:7]2[CH2:8][CH2:9][O:10][C:6]=2[CH:5]=[CH:4][C:3]=1[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1.C([Li])(C)(C)C.[C:22](=[O:24])=[O:23].[OH-].[Na+]>C1COCC1.CCOCC>[C:11]1([C:3]2[C:2]([C:22]([OH:24])=[O:23])=[C:7]3[CH2:8][CH2:9][O:10][C:6]3=[CH:5][CH:4]=2)[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1

Participants

7

Reactant 4

HCID 280Carbon DioxideHCID 14798Sodium HydroxideHCID 218521872,3-Dihydro-4-iodo-5-phenylbenzofuranHCID 178418306HCID 178418306, compound

Product 1

HCID 218521852,3-Dihydro-5-phenyl-4-benzofurancarboxylic acidYield 67%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Procedure

A magnetically stirred solution of 2,3-dihydro-4-iodo-5-phenylbenzofuran (1.60 g, 4.97 mmol) in anhydrous THF (40 mL) under nitrogen at -78° C. was treated with tert-butyllithium (1.73 M in pentane, 6.10 mL, 10.6 mmol), keeping the temperature less than -65° C., throughout. The solution was stirred for 0.5 h and treated with anhydrous carbon dioxide over 1 h at such a rate as to keep the temperature below -60° C. during addition. The solution was stirred for 2 h, allowed to warm to room temperature, and treated with Et2O, ice (100 g), and 1 N NaOH (200 mL). The layers were separated and the organic portion was further extracted with fresh 1 N NaOH (2×200 mL). The combined organic extracts were acidified with concentrated HCl, extracted with CH2Cl2 (3×150 mL), and the extracts washed with brine (200 mL), dried (MgSO4), filtered, and concentrated in vacuo to give 0.795 g (67%) of the title compound: 1H NMR (300 MHz, CDCl3)δ 3.45 (t, J=8.5 Hz, 2H), 4.65 (t, J=8.5 Hz, 2H), 6.93 (d, J=8 Hz, 1H), 7.14 (d, J=8 Hz, 1H), 7.29-7.42 (m, 5H), 11.2 (br s, 1H).

Workup

  1. customthe temperature less than -65° C.
  2. customthe temperature below -60° C.
  3. additionduring addition
  4. stirringThe solution was stirred for 2 h
  5. customThe layers were separated
  6. extractionthe organic portion was further extracted with fresh 1 N NaOH (2×200 mL)
  7. extractionextracted with CH2Cl2 (3×150 mL)
  8. washthe extracts washed with brine (200 mL)
  9. dry with materialdried (MgSO4)
  10. filtrationfiltered
  11. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-a917370114244fbcb90d0f0a770dc649
Source dataset
uspto-grants-1999_09
Patent number
US05948817

Reaction notes

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