Sodium Hydroxide → 4-Methoxy-1H-1lambda~6~,2-benzothiazole-1,1,3(2H)-trione

HRID 1995385Notes

Reaction equation

HRID 1995385 reaction equation
N[C:2]1[C:6]2[C:7]([O:11][CH3:12])=[CH:8][CH:9]=[CH:10][C:5]=2[S:4](=[O:14])(=[O:13])[N:3]=1.[OH-:15].[Na+]>O>[CH3:12][O:11][C:7]1[C:6]2[C:2](=[O:15])[NH:3][S:4](=[O:14])(=[O:13])[C:5]=2[CH:10]=[CH:9][CH:8]=1

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 155671643-Amino-4-methoxy-1,2-benzoisothiazole-1,1-dioxide

Product 1

HCID 149840514-Methoxy-1H-1lambda~6~,2-benzothiazole-1,1,3(2H)-trioneYield 79.7%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

2.5 gm (11.8 mmols) of 3-amino-4-methoxy-1,2-benzoisothiazole-1,1-dioxide were refluxed for 3 hours in a solution of 0.47 gm (11.8 mmols) of sodium hydroxide in 300 ml of water. The reaction mixture was filtered while still hot and acidified with hydrochloric acid. The resulting precipitate was filtered off, dried and recrystallized from benzene/ethyl acetate. 2.0 gm (9.4 mmols) of 4-methoxy-1,2-benzoisothiazol-3(2H)-one-1,1-dioxide (m.p.: 224° C.) were obtained, which were dissolved in 500 ml of ethylene chloride, and the solution was admixed with 10 gm (40 mmols) of boron tribromide. The reaction mixture was slowly heated and refluxed for 1 hour. The reaction mixture was evaporated in vacuo and then repeatedly evaporated in vacuo after addition of ethanol. The obtained product was recrystallized from water, yielding 1.6 gm (68% of theory) of 4-hydroxy-1,2-benzoisothiazol-3(2H)-one-1,1-dioxide.

Workup

  1. filtrationThe reaction mixture was filtered while still hot and
  2. filtrationThe resulting precipitate was filtered off
  3. customdried
  4. customrecrystallized from benzene/ethyl acetate

Sources & evidence

ORD record
ord-5e6c621f47894b16b00ae9bb0ea8685a
Source dataset
uspto-grants-1983_09
Patent number
US04404230

Reaction notes

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