Sodium hydride → Ethyl 2-bromoimidazo[5,1-b]thiazole-7-carboxylate

HRID 1444160Notes

Reaction equation

HRID 1444160 reaction equation
[N+:1]([CH2:3][C:4]([O:6][CH2:7][CH3:8])=[O:5])#[C-:2].[H-].[Na+].Br[C:12]1[S:13][C:14]([Br:17])=[CH:15][N:16]=1>CN(C)C=O.O1CCCC1.[Cl-].[Na+].O>[Br:17][C:14]1[S:13][C:12]2=[C:3]([C:4]([O:6][CH2:7][CH3:8])=[O:5])[N:1]=[CH:2][N:16]2[CH:15]=1

Participants

7

Reactant 3

HCID 24758Sodium hydrideHCID 3123942,5-DibromothiazoleHCID 533707Ethyl isocyanoacetate

Product 1

HCID 59168405Ethyl 2-bromoimidazo[5,1-b]thiazole-7-carboxylate

Reagents, catalysts & solvents 3

HCID 6228DimethylformamideSolventHCID 8028TetrahydrofuranSolventHCID 57417360Sodium chloride; waterSolvent

Procedure

Ethyl isocyanoacetate (0.9 ml, 8.2 mmol) was gradually added dropwise to a suspension of sodium hydride (60% in mineral oil, 378 mg, 9.4 mmol) in N,N-dimethylformamide (5 ml) in an argon atmosphere under ice cooling. The mixture was stirred at the same temperature for 2 hr. This solution was added dropwise to a solution of 2,5-dibromothiazole (1.0 g, 4.1 mmol) in tetrahydrofuran (13 ml) cooled to −20° C. (brine/ice water) through a cannula over a period of 20 min, and, while allowing the temperature to rise to around 0° C., the mixture was stirred for 2 hr. After the completion of the reaction, saturated brine was added thereto, and the mixture was extracted with ethyl acetate (20 ml×5). The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed by distillation under the reduced pressure. The residue was washed with ethyl acetate to give ethyl 2-bromoimidazo[5,1-b]thiazole-7-carboxylate. The solvent was removed from the ethyl acetate washing liquor by distillation, and the residue was purified by chromatography on silica gel (hexane:ethyl acetate=1:2). The resultant purification product was combined with the crystal prepared above to give ethyl 2-bromoimidazo[5,1-b]thiazole-7-carboxylate (1.1 g, 90%) as a white solid.

Workup

  1. customto rise to around 0° C.
  2. stirringthe mixture was stirred for 2 hr
  3. additionwas added
  4. extractionthe mixture was extracted with ethyl acetate (20 ml×5)
  5. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  6. customthe solvent was removed by distillation under the reduced pressure
  7. washThe residue was washed with ethyl acetate

Sources & evidence

ORD record
ord-79b57e1642e34a1eac478fdd4585de3e
Source dataset
uspto-grants-2010_02
Patent number
US07662841B2

Reaction notes

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