Propanoic acid, 2-bromo-2-methyl-, ethyl ester → HCID 20075033, compound

HRID 703843Notes

Reaction equation

HRID 703843 reaction equation
[CH3:1][N:2]1[CH:6]=[CH:5][N:4]=[C:3]1[C:7]1[CH2:8][O:9][C:10]2[CH:16]=[CH:15][C:14]([OH:17])=[CH:13][C:11]=2[CH:12]=1.CC(C)([O-])C.[K+].Br[C:25]([CH3:32])([CH3:31])[C:26]([O:28][CH2:29][CH3:30])=[O:27]>C(O)(C)(C)C>[CH3:1][N:2]1[CH:6]=[CH:5][N:4]=[C:3]1[C:7]1[CH2:8][O:9][C:10]2[CH:16]=[CH:15][C:14]([O:17][C:25]([CH3:32])([CH3:31])[C:26]([O:28][CH2:29][CH3:30])=[O:27])=[CH:13][C:11]=2[CH:12]=1

Participants

5

Reactant 3

HCID 11745Propanoic acid, 2-bromo-2-methyl-, ethyl esterHCID 20075045HCID 20075045, compoundHCID 23665647Potassium tert-butoxide

Product 1

HCID 20075033HCID 20075033, compoundYield 68.6%

Reagents, catalysts & solvents 1

HCID 6386tert-ButanolSolvent2×

Procedure

A mixture of 4.56 g (0.02 mol) of 3-(1-methyl-1H-imidazol-2-yl)-2H-1-benzopyran-6-ol [m.p. 210°-215° C., prepared following the procedure described in J. Heterocyclic Chem. 23, 1693 (1986)] and 2.3 g (0.02 mol) of potassium tert.butoxide in 100 ml of tert.butanol is heated, under vigorous stirring, at 50° C. for 30'. A solution of 3.9 g (0.02 mol) of ethyl bromoisobutyrate in 10 ml of tert.butanol is rapidly added dropwise and the resulting mixture refluxed for 4 hours. The solvent is evaporated under vacuum and the residue is taken up with H2O (100 ml) and ethyl acetate. The aqueous solution is separated and extracted again with ethyl acetate (2×100 ml). The combined organic layers are washed with brine and dried over Na2SO4. After removal of the solvent under vacuum, the residue is chromatographed over silica gel (eluant chloroform/methanol 95/5) giving 4.7 g of ethyl 2-[3-(1-methyl-1H-imidazol-2-yl)-2H-1-benzopyran-6-yl]oxy-2-methylpropanoate, colourless oil.

Workup

  1. customprepared
  2. temperaturethe resulting mixture refluxed for 4 hours
  3. customThe solvent is evaporated under vacuum
  4. customThe aqueous solution is separated
  5. extractionextracted again with ethyl acetate (2×100 ml)
  6. washThe combined organic layers are washed with brine
  7. dry with materialdried over Na2SO4
  8. customAfter removal of the solvent under vacuum
  9. customthe residue is chromatographed over silica gel (eluant chloroform/methanol 95/5)

Sources & evidence

ORD record
ord-6b6554f6948646b4af7e081959ed0344
Source dataset
uspto-grants-1991_01
Patent number
US04985440

Reaction notes

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