Reaction #1005938

Reaction equation

1-(4-chloro-phenyl)-3-((Z)-3-tributylstannanyl-but-2-enyloxy)-1H-pyrazole

iodine

→

1-(4-chlorophenyl)-3-[(Z)-3-iodobut-2-enoxy]pyrazole

Solvents

methylene chloride

Conditions

Workup

1. 1
   OtherAfter removal of the solvents in vacuo the crude product
2. 2
   workup.DISSOLUTIONwas dissolved in 200 ml MTBE
3. 3
   workup.ADDITION100 ml 20% aqueous potassium fluoride solution have been added
4. 4
   workup.STIRRINGthe mixture was stirred for 2 h at ambient temperature
5. 5
   OtherThe aqueous layer was separated
6. 6
   Extractionextracted with 20 ml methyl-tert.-butyl ether twice
7. 7
   WashThe combined organic phases have been washed twice with 20 ml of water each,
8. 8
   Dryingdried with sodium sulfate
9. 9
   Otherthe solvents were removed in vacuo
10. 10
    OtherThe crude product (7.2 g) has been purified by chromatography on 50 g silica with methyl-tert.-butylether/hexane (1:20)

Procedure

To 10.0 g (18.6 mmol) 1-(4-chloro-phenyl)-3-((Z)-3-tributylstannanyl-but-2-enyloxy)-1H-pyrazole in 100 ml methylene chloride have been added 4.7 g (18.6 mmol) iodine at ambient temperature with stirring which was continued for 3 h. After removal of the solvents in vacuo the crude product was dissolved in 200 ml MTBE. 100 ml 20% aqueous potassium fluoride solution have been added and the mixture was stirred for 2 h at ambient temperature. The aqueous layer was separated and extracted with 20 ml methyl-tert.-butyl ether twice. The combined organic phases have been washed twice with 20 ml of water each, dried with sodium sulfate, and the solvents were removed in vacuo. The crude product (7.2 g) has been purified by chromatography on 50 g silica with methyl-tert.-butylether/hexane (1:20). Yield 5.9 g, melting point 75-77° C.

Source