Hydrochloric Acid → p-Toluenesulfonic acid

HRID 396940Notes

Reaction equation

HRID 396940 reaction equation
O.Cl.[K].O.[C:5]1([CH3:15])[CH:10]=[CH:9][C:8]([S:11]([OH:14])(=[O:13])=[O:12])=[CH:7][CH:6]=1>O1CCCC1>[CH3:15][C:5]1[CH:10]=[CH:9][C:8]([S:11]([OH:14])(=[O:13])=[O:12])=[CH:7][CH:6]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 962WaterHCID 521998p-Toluenesulfonic acid monohydrateHCID 5462222Potassium

Product 1

HCID 6101p-Toluenesulfonic acidYield 189%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
3 °C

Procedure

40 ml of water and 30 g (0.296 mole) of 36% hydrochloric acid were placed in a 300-ml flask as a reactor, and cooled to 3° C. Thereto was dropwise added, at 2 to 5° C. with stirring, 48.0 g (0.056 mole) of an aqueous solution of a potassium salt of 2-amino-5-fluororothophenol, followed by stirring for 1 hour. The system had a pH of 5.23. Thereto were added 9.7 g (0.051 mole) of p-toluenesulfonic acid monohydrate and 15 ml of tetrahydrofuran, followed by stirring for 30 minutes. Thereto was added 8.1 g (0.055 mole) of D-alanine-N-carboxyanhydride (purity: 78.3%) at 0° C. The resulting mixture was aged at 15 to 20° C. for 18 hours. The resulting crystals were collected by filtration and dried at 60° C. to obtain 16.6 g of a p-toluenesulfonate of [2-(6-fluorobenzothiazolyl)]ethylamine (purity: 93.5%) (the yield was 82.8% relative to the potassium salt of 2-amino-5-fluorothiophenol).

Workup

  1. additionThereto was dropwise added, at 2 to 5° C.
  2. stirringby stirring for 1 hour
  3. stirringby stirring for 30 minutes
  4. filtrationThe resulting crystals were collected by filtration
  5. customdried at 60° C.

Sources & evidence

ORD record
ord-50152b214cfb493fa8bf77a128801db4
Source dataset
uspto-grants-2003_08
Patent number
US06608207B2

Reaction notes

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