Potassium tert-butoxide → (E)-ethyl 1-(4-fluorophenyl)-2-(2,3,6-trifluorostyryl)-1H-imidazole-5-carboxylate

HRID 2368480Notes

Reaction equation

HRID 2368480 reaction equation
[Br-].C1([P+](C2C=CC=CC=2)(C2C=CC=CC=2)[CH2:9][C:10]2[C:15]([F:16])=[CH:14][CH:13]=[C:12]([F:17])[C:11]=2[F:18])C=CC=CC=1.CC(C)([O-])C.[K+].[F:37][C:38]1[CH:43]=[CH:42][C:41]([N:44]2[C:48]([C:49]([O:51][CH2:52][CH3:53])=[O:50])=[CH:47][N:46]=[C:45]2[CH:54]=O)=[CH:40][CH:39]=1>C1COCC1>[F:37][C:38]1[CH:39]=[CH:40][C:41]([N:44]2[C:48]([C:49]([O:51][CH2:52][CH3:53])=[O:50])=[CH:47][N:46]=[C:45]2/[CH:54]=[CH:9]/[C:10]2[C:15]([F:16])=[CH:14][CH:13]=[C:12]([F:17])[C:11]=2[F:18])=[CH:42][CH:43]=1

Participants

5

Reactant 3

HCID 23665647Potassium tert-butoxideHCID 86677543ethyl 1-(4-fluorophenyl)-2-formyl-1H-imidazole-5-carboxylateHCID 86677545Triphenyl(2,3,6-trifluorobenzyl)phosphonium bromide

Product 1

HCID 86677544(E)-ethyl 1-(4-fluorophenyl)-2-(2,3,6-trifluorostyryl)-1H-imidazole-5-carboxylate

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a solution of triphenyl(2,3,6-trifluorobenzyl)phosphonium bromide (428 mg, 0.88 mmol) in THF at 0° C. was added potassium tert-butoxide (99 mg, 0.88 mmol). After the reaction was stirred for 1 h, it was warmed to room temperature and a solution of ethyl 1-(4-fluorophenyl)-2-formyl-1H-imidazole-5-carboxylate (16) (210 mg, 0.80) in THF (1 mL) was added. The mixture was refluxed for 6 h, cooled to room temperature, filtered, and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel (0-40% EtOAc in hexanes, Rf=0.2 in 80/20 hexanes/ethyl acetate) to yield (E)-ethyl 1-(4-fluorophenyl)-2-(2,3,6-trifluorostyryl)-1H-imidazole-5-carboxylate (17) as the only stereoisomer.

Workup

  1. temperatureThe mixture was refluxed for 6 h
  2. temperaturecooled to room temperature
  3. filtrationfiltered
  4. concentrationconcentrated in vacuo
  5. customThe residue was purified by flash column chromatography on silica gel (0-40% EtOAc in hexanes, Rf=0.2 in 80/20 hexanes/ethyl acetate)

Sources & evidence

ORD record
ord-4dc0c12f07454f51928864d1ecd3ba03
Source dataset
uspto-grants-2014_04
Patent number
US08703776B2

Reaction notes

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