Hydrochloric Acid → 2-Chloro-5-fluoro-1,3-benzothiazole

HRID 1707926Notes

Reaction equation

HRID 1707926 reaction equation
N([O-])=O.[Na+].N[C:6]1[S:7][C:8]2[CH:14]=[CH:13][C:12]([F:15])=[CH:11][C:9]=2[N:10]=1.[ClH:16]>O.[Cu]>[Cl:16][C:6]1[S:7][C:8]2[CH:14]=[CH:13][C:12]([F:15])=[CH:11][C:9]=2[N:10]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 8212032-Amino-5-fluorobenzothiazoleHCID 23668193Sodium Nitrite

Product 1

HCID 112408962-Chloro-5-fluoro-1,3-benzothiazoleYield 49%

Reagents, catalysts & solvents 2

HCID 23978CopperCatalystHCID 962WaterSolvent

Procedure

A solution of 242 g (3.5 mol) of sodium nitrite in 440 ml of water is added dropwise with stirring to a mixture, cooled to -10° C., of 147 g (0.87 mol) of 2-amino-5-fluoro-benzothiazole, 1700 ml of conc. hydrochloric acid and 20 g of copper power and the reaction mixture is stirred at 0° C. for 60 minutes and at 50° C. for a further 60 minutes. It is then extracted with chloroform and the solvent is carefully removed by distillation from the organic phase in a water-jet vacuum. 80 g (49% of theory) of 2-chloro-5-fluoro-benzothiazole are obtained as a crystalline residue of melting point 69° C.

Workup

  1. stirringthe reaction mixture is stirred at 0° C. for 60 minutes and at 50° C. for a further 60 minutes
  2. extractionIt is then extracted with chloroform
  3. customthe solvent is carefully removed by distillation from the organic phase in a water-jet vacuum

Sources & evidence

ORD record
ord-076a092f5c5a46d5a0652ec3162c4396
Source dataset
uspto-grants-1994_10
Patent number
US05356864

Reaction notes

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