N-Fluorobenzenesulfonimide → Methyl [2-(2,2-dimethylpropyl)benzoxazol-5-yl]fluoroacetate

HRID 48155Notes

Reaction equation

HRID 48155 reaction equation
C([N-]C(C)C)(C)C.[Li+].[CH2:9]([C:11]([CH2:28]C)([CH3:27])[CH2:12][C:13]1[O:14][C:15]2[CH:21]=[CH:20][C:19]([CH2:22][C:23]([O:25][CH3:26])=[O:24])=[CH:18][C:16]=2[N:17]=1)C.C1C=CC(S(N(S(C2C=CC=CC=2)(=O)=O)[F:40])(=O)=O)=CC=1>O1CCCC1>[CH3:9][C:11]([CH3:28])([CH3:27])[CH2:12][C:13]1[O:14][C:15]2[CH:21]=[CH:20][C:19]([CH:22]([F:40])[C:23]([O:25][CH3:26])=[O:24])=[CH:18][C:16]=2[N:17]=1

Participants

5

Reactant 3

HCID 588007N-FluorobenzenesulfonimideHCID 2724682Lithium diisopropylamideHCID 91130712HCID 91130712, compound

Product 1

HCID 22742089Methyl [2-(2,2-dimethylpropyl)benzoxazol-5-yl]fluoroacetateYield 65.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-78 °C

Procedure

A solution of lithium diisopropylamide (2.0M solution in tetrahydrofuran/ethylbenzene/heptane, 3.85 ml, 0.0077 mol) was added dropwise to a solution of methyl [2-(2,2-diethylpropyl)benzoxazol-5-yl]acetate (2.0 g, 0.0077 mol) in tetrahydrofuran (40 ml) at −78° C. under a nitrogen atmosphere and the mixture was stirred at −78° C. for 1 hour. A solution of N-fluorobenzenesulfonimide (2.42 g, 0.0077 mol) in tetrahydrofuran (10 ml) was added dropwise and the mixture was stirred at −70° C. for a further 1 hour. The cooling bath was removed and the mixture allowed to warm to room temperature over a period of 20 hours. The reaction mixture was diluted with water, acidified with dilute aqueous hydrochloric acid and extracted with ethyl acetate. The organic extracts were combined, washed with water, dried over anhydrous magnesium sulfate, filtered and the filtrate was evaporated in vacuo. The residue was purified by flash column chromatography on silica gel, eluting with ethyl acetate:dichloromethane 5:95, and was further purified by column chromatography on silica gel, eluting with ethyl acetate:hexane 1:3, to give methyl [2-(2,2-dimethylpropyl)benzoxazol-5-yl]fluoroacetate (1.4 g).

Workup

  1. stirringthe mixture was stirred at −70° C. for a further 1 hour
  2. customThe cooling bath was removed
  3. temperatureto warm to room temperature over a period of 20 hours
  4. additionThe reaction mixture was diluted with water
  5. extractionextracted with ethyl acetate
  6. washwashed with water
  7. dry with materialdried over anhydrous magnesium sulfate
  8. filtrationfiltered
  9. customthe filtrate was evaporated in vacuo
  10. customThe residue was purified by flash column chromatography on silica gel
  11. washeluting with ethyl acetate:dichloromethane 5:95
  12. customwas further purified by column chromatography on silica gel
  13. washeluting with ethyl acetate:hexane 1:3

Sources & evidence

ORD record
ord-67641d2532c94f69b97c5f70d2364ba1
Source dataset
uspto-grants-2004_03
Patent number
US06703347B2

Reaction notes

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