N-bromobutanimide → 3-Formyl-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester

HRID 1773539Notes

Reaction equation

HRID 1773539 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[CH:7]=[C:8]2[S:14][CH:13]=[C:12]([CH3:15])[C:9]2=[N:10][CH:11]=1)=[O:5])[CH3:2].BrN1C(=[O:22])CCC1=O>C(Cl)(Cl)(Cl)Cl.CC(N=NC(C#N)(C)C)(C#N)C>[CH2:1]([O:3][C:4]([C:6]1[CH:7]=[C:8]2[S:14][CH:13]=[C:12]([CH:15]=[O:22])[C:9]2=[N:10][CH:11]=1)=[O:5])[CH3:2]

Participants

5

Reactant 2

HCID 67184N-bromobutanimideHCID 580561733-Methyl-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester

Product 1

HCID 866613713-Formyl-thieno[3,2-b]pyridine-6-carboxylic acid ethyl esterYield 62.7%

Reagents, catalysts & solvents 2

HCID 6547AzobisisobutyronitrileCatalystHCID 5943Carbon TetrachlorideSolvent

Conditions

Temperature
80 °C

Procedure

To a solution of 3-methyl-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester (1.2 g) in carbon tetrachloride (50 mL) was added N-bromosuccinimide (2.4 g) followed by AIBN (50 mg) and the resulting mixture was heated at reflux for 4 hours. The reaction mixture was cooled; the solids were removed by filtrations and copiously washed with carbon tetrachloride. The filtrate was evaporated under reduced pressure, the residue was dissolved in dimethyl sulfoxide (20 mL) and the resulting mixture was heated at 80° C. for 1 hour. The reaction mixture was cooled, diluted with water, basified by addition of a saturated aqueous solution of sodium bicarbonate and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and evaporated under reduced pressure. The residue was purified by flash chromatography (acetone/DCM, 5/95) to give 0.8 g of 3-formyl-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester.

Workup

  1. temperaturethe resulting mixture was heated
  2. temperatureat reflux for 4 hours
  3. temperatureThe reaction mixture was cooled
  4. customthe solids were removed by filtrations
  5. washcopiously washed with carbon tetrachloride
  6. customThe filtrate was evaporated under reduced pressure
  7. dissolutionthe residue was dissolved in dimethyl sulfoxide (20 mL)
  8. temperatureThe reaction mixture was cooled
  9. additiondiluted with water
  10. additionbasified by addition of a saturated aqueous solution of sodium bicarbonate
  11. extractionextracted with ethyl acetate
  12. washThe combined organic layers were washed with brine
  13. dry with materialdried over anhydrous sodium sulfate
  14. filtrationfiltered
  15. customevaporated under reduced pressure
  16. customThe residue was purified by flash chromatography (acetone/DCM, 5/95)

Sources & evidence

ORD record
ord-6c4e2a5b726a4ad0b723eb98fb4f8df9
Source dataset
uspto-grants-2016_02
Patent number
US09255110B2

Reaction notes

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