Phosphoric Acid → 3-Chloro-4,5,6,7-tetrahydro-1,2-benzisothiazole

HRID 610613Notes

Reaction equation

HRID 610613 reaction equation
O[C:2]1[C:6]2[CH2:7][CH2:8][CH2:9][CH2:10][C:5]=2[S:4][N:3]=1.Cl.[NH+]1C=CC=CC=1.P(=O)(O)(O)O.P(Cl)(Cl)([Cl:25])=O>>[Cl:25][C:2]1[C:6]2[CH2:7][CH2:8][CH2:9][CH2:10][C:5]=2[S:4][N:3]=1

Participants

5

Reactant 4

HCID 1004Phosphoric AcidHCID 24813Phosphorus oxychlorideHCID 21584435Pyridinium hydrochlorideHCID 178519008HCID 178519008, compound

Product 1

HCID 107735623-Chloro-4,5,6,7-tetrahydro-1,2-benzisothiazole

Conditions

Temperature
90 °C

Procedure

A mixture of 3-hydroxy-4,5,6,7-tetrahydro-1,2-benzisothiazole 22a (4.74 g), pyridinium hydrochloride (12.7 g), phosphoric acid (2.1 g) and phosphorus oxychloride (25 mL) was stirred at 90° C. for 5 h. The reaction mixture was evaporated and ethyl acetate (130 mL) was added to the residue. A saturated solution of sodium hydrogencarbonate (130 mL) was added and after 10 min of stirring the phases were separated. The aqueous phase was extracted with ethyl acetate (2×150 mL) and the combined organic phases were dried and evaporated to give an oil. Column chromatography on silica gel (eluent:toluene-ethyl acetate 1:1) gave the title compound as a yellow oil (2.8 g).

Workup

  1. customThe reaction mixture was evaporated
  2. additionethyl acetate (130 mL) was added to the residue
  3. additionA saturated solution of sodium hydrogencarbonate (130 mL) was added and after 10 min
  4. stirringof stirring the phases
  5. customwere separated
  6. extractionThe aqueous phase was extracted with ethyl acetate (2×150 mL)
  7. customthe combined organic phases were dried
  8. customevaporated
  9. customto give an oil

Sources & evidence

ORD record
ord-688d0501d59b45c58aa3de19b772c545
Source dataset
uspto-grants-1999_12
Patent number
US05998613

Reaction notes

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