Hydrogen Bromide → 2-Bromo-6-fluoro-1,3-benzothiazole

HRID 2260127Notes

Reaction equation

HRID 2260127 reaction equation
N[C:2]1[S:3][C:4]2[CH:10]=[C:9]([F:11])[CH:8]=[CH:7][C:5]=2[N:6]=1.N([O-])=O.[Na+].[BrH:16]>O.[Cu]Br>[Br:16][C:2]1[S:3][C:4]2[CH:10]=[C:9]([F:11])[CH:8]=[CH:7][C:5]=2[N:6]=1

Participants

6

Reactant 3

HCID 260Hydrogen Bromide2×HCID 3199542-Amino-6-fluorobenzothiazoleHCID 23668193Sodium Nitrite

Product 1

HCID 114923512-Bromo-6-fluoro-1,3-benzothiazole

Reagents, catalysts & solvents 2

HCID 24593copper(I) bromideCatalystHCID 962WaterSolvent3×

Conditions

Temperature
0 °C

Procedure

Slurry 2-amino-6-fluorobenzothiazole (0.255 mol) in water (325 mL), heat to reflux and add 48% hydrobromic acid (130 mL). Maintain at reflux for 20 minutes, cool to 0° C. and add a solution of sodium nitrite (17.56 g, 0.255 mol) in water (90 mL), maintaining a temperature of 0° C. Stir at 0° C. for 15 minutes and add by dropwise addition (while keeping cold) to a rapidly stirring mixture of copper (I) bromide (42.03 g,0.293 mol) in 48% hydrobromic acid (86 mL) and water (225 mL). Stir at room temperature for 20 minutes. Allow to stand overnight, extract into methylene chloride and dry (MgSO4). Evaporate the solvent in vacuo and purify by chromatography to give 2-bromo-6-fluorobenzothiazole.

Workup

  1. temperatureto reflux
  2. temperatureMaintain
  3. temperatureat reflux for 20 minutes
  4. temperaturemaintaining a temperature of 0° C
  5. additionadd by dropwise addition (while keeping cold) to
  6. stirringa rapidly stirring
  7. stirringStir at room temperature for 20 minutes
  8. waitAllow to stand overnight
  9. extractionextract into methylene chloride
  10. dry with materialdry (MgSO4)
  11. customEvaporate the solvent in vacuo
  12. custompurify by chromatography

Sources & evidence

ORD record
ord-67cd80c031be461eaaa8eb67a94be254
Source dataset
uspto-grants-1995_12
Patent number
US05476861

Reaction notes

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