Reaction #77255

Reaction equation

5-nitro-l,2-benzisothiazol-3(2H)-one

phosphorus oxychloride

tributylamine

→

title product

3-Chloro-5-nitro-1,2-benzisothiazole

Solvents

methylene chloride

Conditions

Workup

1. 1
   ExtractionThe resultant aqueous mixture is extracted with methylene chloride
2. 2
   WashThe combined organic extracts are washed sequentially with water and saturated sodium hydrogen carbonate solution
3. 3
   Dryingdried over anhydrous sodium sulfate
4. 4
   Concentrationconcentrated in vacuo
5. 5
   Otherto obtain a gum

Procedure

A mixture of 5-nitro-l,2-benzisothiazol-3(2H)-one (10.0 g, 0.0510 mol), phosphorus oxychloride (40.0 mL, 0.429 mol) and tributylamine (12.0 mL, 0.050 mol) is heated at 103-115° C. for six hours, stirred at room temperature overnight, and poured into an ice-water mixture. The resultant aqueous mixture is extracted with methylene chloride. The combined organic extracts are washed sequentially with water and saturated sodium hydrogen carbonate solution, dried over anhydrous sodium sulfate, and concentrated in vacuo to obtain a gum. Column chromatography of the gum using silica gel and methylene chloride gives the title product as an orange-yellow solid which is identified by NMR spectral analysis.

Source