Sulfuric Acid → 4-hydroxy-1H-1,2-benzisothiazole-1,1,3(2H)-trione

HRID 1995400Notes

Reaction equation

HRID 1995400 reaction equation
N[C:2]1[C:7]2[C:8](=[O:13])[NH:9][S:10](=[O:12])(=[O:11])[C:6]=2[CH:5]=[CH:4][CH:3]=1.N([O-])=[O:15].[Na+].S(=O)(=O)(O)O>Cl>[OH:15][C:2]1[C:7]2[C:8](=[O:13])[NH:9][S:10](=[O:12])(=[O:11])[C:6]=2[CH:5]=[CH:4][CH:3]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 220611904-Amino-2,3-dihydro-1lambda6,2-benzothiazole-1,1,3-trioneHCID 23668193Sodium Nitrite

Product 1

HCID 14865224-hydroxy-1H-1,2-benzisothiazole-1,1,3(2H)-trioneYield 40%

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent2×

Procedure

A solution of 1,2-benzoisothiazol-3(2H)-one-1,1-dioxide-4-diazonium chloride, which was prepared by diazotization of 1.98 gm (10 mmols) of 4-amino-1,2-benzoisothiazol-3(2H)-one-1,1-dioxide with sodium nitrite in dilute hydrochloric acid, was reacted with 150 ml of aqueous 10% sulfuric acid, and the reaction mixture was heated on a water bath until the evolution of nitrogen had ceased. After cooling, the reaction mixture was strongly acidified with concentrated aqueous hydrochloric acid and extracted with ether. The organic phase was evaporated, the residue was dissolved in a little sodium hydrochloride, filtered and again acidified with hydrochloric acid. The crystals formed were recrystallized from water, yielding 0.98 gm (40% of theory) of 4-hydroxy-1,2-benzoisothiazol-3(2H)-one-1,1-dioxide.

Workup

  1. temperaturethe reaction mixture was heated on a water bath until the evolution of nitrogen
  2. temperatureAfter cooling
  3. extractionextracted with ether
  4. customThe organic phase was evaporated
  5. dissolutionthe residue was dissolved in a little sodium hydrochloride
  6. filtrationfiltered
  7. customThe crystals formed
  8. customwere recrystallized from water

Sources & evidence

ORD record
ord-40a098f59582454b85a027e6c2d2dc52
Source dataset
uspto-grants-1983_09
Patent number
US04404230

Reaction notes

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