Imidazole → 5-[2-(1-Imidazolyl)ethoxy]benzo[b]thiophene-2-carboxylic acid methyl ester

HRID 648036Notes

Reaction equation

HRID 648036 reaction equation
[H-].[Na+].[NH:3]1[CH:7]=[CH:6][N:5]=[CH:4]1.[CH3:8][O:9][C:10]([C:12]1[S:16][C:15]2[CH:17]=[CH:18][C:19]([O:21][CH2:22][CH2:23]Cl)=[CH:20][C:14]=2[CH:13]=1)=[O:11].O>CN(C)C=O>[CH3:8][O:9][C:10]([C:12]1[S:16][C:15]2[CH:17]=[CH:18][C:19]([O:21][CH2:22][CH2:23][N:3]3[CH:7]=[CH:6][N:5]=[CH:4]3)=[CH:20][C:14]=2[CH:13]=1)=[O:11]

Participants

6

Reactant 4

HCID 795ImidazoleHCID 962WaterHCID 24758Sodium hydrideHCID 136630005-(2-Chloroethoxy)benzo[b]thiophene-2-carboxylic acid methyl ester

Product 1

HCID 136630165-[2-(1-Imidazolyl)ethoxy]benzo[b]thiophene-2-carboxylic acid methyl esterYield 33.1%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

Sodium hydride (0.22 g. of 50% dispersion in mineral oil) was added portionwise with stirring to a solution of imidazole (0.306 g.) in dry N,N-dimethylformamide (10 ml.) and the mixture was stirred at room temperature for 30 minutes and then warmed for a few minutes. 5-(2-Chloroethoxy)benzo[b]thiophene-2-carboxylic acid methyl ester (1.22 g.) was then added and the mixture was heated on a steam bath for 5 hours, and then cooled and poured into water. The mixture was extracted several times with ethyl acetate and the combined extracts were washed well with water and dried (Na2SO4). Evaporation of the solvent gave an oil which was chromatographed on silica gel. Elution with chloroform gave first mineral oil and some impurity followed by pure product. The product containing fractions were evaporated to give a solid which was crystallized from ethyl acetate/petrol (b.p. 60°-80°) to give 5-[2-(1-imidazolyl)ethoxy]benzo[b]thiophene-2-carboxylic acid methyl ester (0.45 g.), m.p. 127°-129° C.

Workup

  1. temperaturewarmed for a few minutes
  2. temperaturethe mixture was heated on a steam bath for 5 hours
  3. temperaturecooled
  4. extractionThe mixture was extracted several times with ethyl acetate
  5. washthe combined extracts were washed well with water
  6. dry with materialdried (Na2SO4)
  7. customEvaporation of the solvent
  8. customgave an oil which
  9. customwas chromatographed on silica gel
  10. washElution with chloroform
  11. customgave first mineral oil
  12. additionThe product containing fractions
  13. customwere evaporated
  14. customto give a solid which
  15. customwas crystallized from ethyl acetate/petrol (b.p. 60°-80°)

Sources & evidence

ORD record
ord-518df047e0b44bb9b37cf4e09711cd49
Source dataset
uspto-grants-1983_10
Patent number
US04410539

Reaction notes

Loading…