Ethoxzolamide → 6-Hydroxy-1,3-benzothiazole-2-sulfonamide

HRID 615599Notes

Reaction equation

HRID 615599 reaction equation
C([O:3][C:4]1[CH:16]=[CH:15][C:7]2[N:8]=[C:9]([S:11]([NH2:14])(=[O:13])=[O:12])[S:10][C:6]=2[CH:5]=1)C.[Cl-].[Al+3].[Cl-].[Cl-]>ClC(Cl)C.[OH-].[Na+].O>[OH:3][C:4]1[CH:16]=[CH:15][C:7]2[N:8]=[C:9]([S:11]([NH2:14])(=[O:13])=[O:12])[S:10][C:6]=2[CH:5]=1

Participants

6

Reactant 2

HCID 3295EthoxzolamideHCID 6451240Aluminum(III) Chloride

Product 1

HCID 68521296-Hydroxy-1,3-benzothiazole-2-sulfonamide

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 63651,1-DichloroethaneSolventHCID 14798Sodium HydroxideSolvent

Procedure

6-Ethoxybenzothiazole-2-sulfonamide (1.72 g, 6.7 mmol) was dissolved in dichloroethane (26 ml) and cooled to 20°. Aluminum chloride (4 g) was added portionwise such that the temperature remained 20°. After complete addition, the mixture was stirred at room temperature for 24 hours. Stirring was discontinued and after 0.5 hour, the supernatant was decanted from a tarry-like residue. This residue was cooled in an ice-water mixture and a cold solution of concentrated HCl (3 ml) in water (40 ml) was added as rapidly as possible with stirring. The resulting mixture was stirred for an hour and filtered. The solid was washed with water and suction dried to give 0.5-0.8 g. This material was combined with that from further working of the supernatant and dissolved in 20% NaOH solution, diluted to 100 ml with water and filtered. The filtrate was slowly acidified with concentrated hydrochloric acid (pH 3) and the resulting tan solid was filtered, washed with water and dried at 60°-80° C. under vacuum: total yield 1.3 g, m.p. 225°-228° C.

Workup

  1. temperaturecooled to 20°
  2. customremained 20°
  3. additionAfter complete addition
  4. stirringStirring
  5. waitwas discontinued and after 0.5 hour
  6. customthe supernatant was decanted from a tarry-like residue
  7. temperatureThis residue was cooled in an ice-water mixture
  8. additiona cold solution of concentrated HCl (3 ml) in water (40 ml) was added as rapidly as possible
  9. stirringwith stirring
  10. stirringThe resulting mixture was stirred for an hour
  11. filtrationfiltered
  12. washThe solid was washed with water and suction
  13. customdried
  14. customto give 0.5-0.8 g
  15. filtrationfiltered
  16. filtrationthe resulting tan solid was filtered
  17. washwashed with water
  18. customdried at 60°-80° C. under vacuum

Sources & evidence

ORD record
ord-f1290a5dd99f4393b0f524a508ccad9d
Source dataset
uspto-grants-1985_02
Patent number
US04500538

Reaction notes

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