Benzisothiazole → 1,2-Benzisothiazole, 5-nitro-

HRID 1681269Notes

Reaction equation

HRID 1681269 reaction equation
[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[S:11][N:10]=[CH:9][C:8]=2[CH:12]=1)([O-:3])=[O:2].[N+:13]([C:16]1[C:24]2[S:23][N:22]=[CH:21][C:20]=2[CH:19]=[CH:18][CH:17]=1)([O-:15])=[O:14].S1C2C=CC=CC=2C=N1.[N+]([O-])([O-])=O.[K+]>S(=O)(=O)(O)O>[N+:13]([C:12]1[C:8]2[CH:9]=[N:10][S:11][C:7]=2[CH:6]=[CH:5][CH:4]=1)([O-:15])=[O:14].[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[S:11][N:10]=[CH:9][C:8]=2[CH:12]=1)([O-:3])=[O:2].[N+:13]([C:16]1[C:24]2[S:23][N:22]=[CH:21][C:20]=2[CH:19]=[CH:18][CH:17]=1)([O-:15])=[O:14]

Participants

8

Reactant 4

HCID 9225BenzisothiazoleHCID 24434Potassium NitrateHCID 1984101,2-Benzisothiazole, 5-nitro-HCID 1986561,2-Benzisothiazole, 7-nitro-

Product 3

HCID 1984101,2-Benzisothiazole, 5-nitro-HCID 1986561,2-Benzisothiazole, 7-nitro-HCID 19387300HCID 19387300, compound

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Conditions

Temperature
-40 °C

Procedure

P.2 4-Nitrobenzisothiazole, 5-nitrobenzisothiazole and 7-nitrobenzisothiazole 300 g of benzisothiazole are added, with cooling, to 750 ml of concentrated sulfuric acid, the solution is cooled to -40° C., and 227.5 g of potassium nitrate are added in portions, in such a manner that the temperature does not rise above room temperature. After standing at room temperature for 15 hours, the reaction mixture is poured onto ice and the solid portion is filtered off and dried. The product is chromatographed on silica gel with tetrahydrofuran:methylene chloride:hexane 5:10:85. After evaporation, there are isolated from the fractions 5.5% of the theorectical yield of 4-nitrobenzisothiazole, 56.5% of the theoretical yield of 5-nitrobenzisothiazole and 36.8% of the theoretical yield of 7-nitrobenzisothiazole (compounds 16, 11 and 1, Table).

Workup

  1. customdoes not rise above room temperature
  2. additionthe reaction mixture is poured onto ice
  3. filtrationthe solid portion is filtered off
  4. customdried
  5. customThe product is chromatographed on silica gel with tetrahydrofuran:methylene chloride:hexane 5:10:85
  6. customAfter evaporation, there

Sources & evidence

ORD record
ord-1159bcb776a149679a1797dd68b982ab
Source dataset
uspto-grants-1992_12
Patent number
US05169951

Reaction notes

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