Methane → 1-Benzofuran-6-carboxylic acid

HRID 2181650Notes

Reaction equation

HRID 2181650 reaction equation
[OH:1][C:2]1[CH:3]=[C:4]([CH:9]=[CH:10][C:11]=1[C:12]#[C:13][Si](C)(C)C)[C:5]([O:7]C)=[O:6].C.CO.[OH-].[Na+]>CCO.CCN(CC)CC.[Cu]I>[O:1]1[C:2]2[CH:3]=[C:4]([C:5]([OH:7])=[O:6])[CH:9]=[CH:10][C:11]=2[CH:12]=[CH:13]1

Participants

7

Reactant 4

HCID 297MethaneHCID 887MethanolHCID 14798Sodium HydroxideHCID 22481756Methyl 3-hydroxy-4-[2-(trimethylsilyl)ethynyl]benzoate

Product 1

HCID 178672341-Benzofuran-6-carboxylic acidYield 93.3%

Reagents, catalysts & solvents 2

HCID 24350Copper(1+) iodide; Copper(I) iodide; Cuprous iodide; Cuprous iodide (CuI)CatalystHCID 22663003EtOH triethylamineSolvent

Conditions

Temperature
75 °C

Procedure

Methyl 3-hydroxy-4-[(trimethylsilyl)ethynyl]benzoate (3.0 g, 12.1 mmol) is dissolved in 1:1 EtOH/Et3N (30 mL), is treated with CuI (114 mg, 0.6 mmol), and the reaction is warmed to 75° C. for 3 h. The mixture is treated with DARCO and MeOH (15 mL) and heated to reflux for 1 h. The reaction is filtered through a fine fritted-glass funnel, the filtrate is treated with 3N NaOH (24.2 ml, 72.5 mmol), and the mixture is stirred overnight at RT. The mixture is concentrated to dryness, the residue is dissolved in H2O (20 mL), and the pH of the mixture is adjusted to 2 with 12N HCl. The resulting yellow precipitate is collected, washed with water, and is dried to give 1.83 g (93%) of benzofuran-6-carboxylic acid as a tan solid. HRMS (FAB) calcd for C9H6O3+H: 163.0395, found 163.0389 (M+H)+.

Workup

  1. temperatureheated
  2. temperatureto reflux for 1 h
  3. filtrationThe reaction is filtered through a fine fritted-glass funnel
  4. concentrationThe mixture is concentrated to dryness
  5. dissolutionthe residue is dissolved in H2O (20 mL)
  6. customThe resulting yellow precipitate is collected
  7. washwashed with water
  8. customis dried

Sources & evidence

ORD record
ord-b05f5983b46946729961f375a5895c4d
Source dataset
uspto-grants-2005_05
Patent number
US06894042B2

Reaction notes

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