Reaction #2329068

Reaction equation

water

2-bromo-3-chloro-5-methoxy-1-{4-[5-(trifluoromethyl)(2-pyridyl)]piperazinyl}benzene

boron trichloride

dry-ice acetone

→

subject compound

Yield 46.3%

4-bromo-5-chloro-3-{4-[5-(trifluoromethyl)(2-pyridyl)]piperazinyl)phenol

Yield 46.3%

Solvents

methylene chloride

methylene chloride

Conditions

Workup

1. 1
   workup.ADDITIONUpon completion of addition the reaction mixture
2. 2
   TemperatureAfter this time the reaction mixture was cooled in an ice/water bath
3. 3
   OtherThe organic layer was separated
4. 4
   Extractionthe aqueous layer was extracted with one 15 mL portion of methylene chloride
5. 5
   Dryingdried with sodium sulfate
6. 6
   FiltrationThe mixture was filtered
7. 7
   Concentrationthe filtrate was concentrated under reduced pressure to a residue
8. 8
   OtherThe residue was purified with column chromatography on silica gel using as eluants
9. 9
   Concentrationconcentrated under reduced pressure

Procedure

A stirred solution of 0.38 gram (0.00084 mole) of 2-bromo-3-chloro-5-methoxy-1-{4-[5-(trifluoromethyl)(2-pyridyl)]piperazinyl}benzene and 0.78 gram (0.0021 mole) of n-tetrabutylammonium iodide in 30 mL of methylene chloride was cooled in a dry-ice/acetone bath and 2.1 mL (0.0021 mole, a 1.0M solution in methylene chloride) of boron trichloride was added dropwise. Upon completion of addition the reaction mixture was kept cold in the dry-ice/acetone bath for an additional 30-minute period, then it was allowed to warm to ambient temperature where it stirred during a three-hour period. After this time the reaction mixture was cooled in an ice/water bath and 15 mL of water was added. The organic layer was separated and the aqueous layer was extracted with one 15 mL portion of methylene chloride. The organic layer and the extract were combined and dried with sodium sulfate. The mixture was filtered, and the filtrate was concentrated under reduced pressure to a residue. The residue was purified with column chromatography on silica gel using as eluants: 50% hexane in methylene chloride, then 100% methylene chloride, and finally 2% methanol in methylene chloride. The appropriate fractions were combined and concentrated under reduced pressure, yielding 0.17 gram of the subject compound. The NMR spectrum was consistent with the proposed structure.

Source