Acetic Anhydride → 2-Bromoimidazo[5,1-b]thiazole

HRID 1444168Notes

Reaction equation

HRID 1444168 reaction equation
C(OC(=O)C)(=O)C.[Br:8][C:9]1[S:13][C:12]2=[C:14](C(O)=O)[N:15]=[CH:16][N:11]2[CH:10]=1>ClC1C=CC(Cl)=CC=1Cl.CCCCCC>[Br:8][C:9]1[S:13][C:12]2=[CH:14][N:15]=[CH:16][N:11]2[CH:10]=1

Participants

5

Reactant 2

HCID 7918Acetic AnhydrideHCID 591684042-Bromoimidazo(4,3-b)(1,3)thiazole-7-carboxylic acid

Product 1

HCID 104654682-Bromoimidazo[5,1-b]thiazoleYield 67.3%

Reagents, catalysts & solvents 2

HCID 131,2,4-TrichlorobenzeneSolventHCID 8058HexaneSolvent

Conditions

Temperature
150 °C

Procedure

Acetic anhydride (0.1 ml, 1.06 mmol) was added to a solution of 2-bromoimidazo[5,1-b]thiazole-7-carboxylic acid (38 mg, 0.15 mmol) in 1,2,4-trichlorobenzene (1 ml), and the mixture was stirred at 150° C. for 2 hr. The reaction solution was allowed to cool to room temperature, was diluted with hexane, and was extracted with 1 M hydrochloric acid (2 ml×3). The aqueous layer was neutralized with a 2 M aqueous solution of sodium hydroxide and was then extracted with ethyl acetate (4 ml×3). The organic layer was washed with saturated brine and was dried over anhydrous sodium sulfate. The solvent was then removed by distillation under the reduced pressure, and the residue was purified by column chromatography on silica gel (hexane:ethyl acetate=1:1→1:2) to give 2-bromoimidazo[5,1-b]thiazole (20.5 mg, 66%) as a white solid.

Workup

  1. temperatureto cool to room temperature
  2. extractionwas extracted with 1 M hydrochloric acid (2 ml×3)
  3. extractionwas then extracted with ethyl acetate (4 ml×3)
  4. washThe organic layer was washed with saturated brine
  5. dry with materialwas dried over anhydrous sodium sulfate
  6. customThe solvent was then removed by distillation under the reduced pressure
  7. customthe residue was purified by column chromatography on silica gel (hexane:ethyl acetate=1:1→1:2)

Sources & evidence

ORD record
ord-6e47651ce1c44242ae3bd2505f3aa805
Source dataset
uspto-grants-2010_02
Patent number
US07662841B2

Reaction notes

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