Phosphorus oxychloride → 3,4-Dichloro-1,2-benzothiazole

HRID 502609Notes

Reaction equation

HRID 502609 reaction equation
P(Cl)(Cl)([Cl:3])=O.[Cl:6][C:7]1[C:12]2[C:13](=O)[NH:14][S:15][C:11]=2[CH:10]=[CH:9][CH:8]=1>>[Cl:3][C:13]1[C:12]2[C:7]([Cl:6])=[CH:8][CH:9]=[CH:10][C:11]=2[S:15][N:14]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 574365604-Chloro-2,3-dihydro-1,2-benzothiazol-3-one

Product 1

HCID 198345773,4-Dichloro-1,2-benzothiazole

Procedure

Phosphorus oxychloride was added slowly to 4-chlorobenzo[d]isothiazol-3(2H)-one (2.34 g). The reaction mixture was heated at reflux overnight. After normal aqueous work-up, the product was purified by column chromatography, on silica gel, eluted with a mixture of 5% ethyl acetate in hexanes to provide 3,4-dichlorobenzo[d]isothiazole. (This method can be used to 1,2-benzisothiozal-3-ones). 1H NMR (300 MHz, DMSO-d6): 8.23-8.31 (m, 1H), 7.62 ppm (d, 2H). MW=204 confirmed by LC-MS, tr=2.38 min (Method B) MH+=205.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureat reflux overnight
  3. customAfter normal aqueous work-up, the product was purified by column chromatography, on silica gel
  4. washeluted with a mixture of 5% ethyl acetate in hexanes

Sources & evidence

ORD record
ord-c15249ddf2d3475da2688eb18e0542e9
Source dataset
uspto-grants-2010_08
Patent number
US07776847B2

Reaction notes

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