Reaction #2329066

Reaction equation

piperazine

2-chloro-5-(trifluoromethyl)pyridine

→

subject compound

Yield 69.5%

5-(trifluoromethyl)-2-pyridylpiperazine

Yield 69.5%

Solvents

acetonitrile

Conditions

Workup

1. 1
   Temperatureat reflux during a two-hour period
2. 2
   Filtrationit was filtered
3. 3
   ConcentrationThe filtrate was concentrated under reduced pressure to a residue
4. 4
   workup.DISSOLUTIONThe residue was dissolved in 75 mL of methylene chloride
5. 5
   Washwashed with two 50 mL portions of water
6. 6
   DryingThe organic layer was dried with sodium sulfate
7. 7
   Filtrationfiltered
8. 8
   Concentrationthe filtrate was concentrated under reduced pressure to a residue
9. 9
   OtherThe residue was purified with column chromatography on silica gel using 100% methylene chloride
10. 10
    Concentrationconcentrated under reduced pressure

Procedure

A stirred solution of 7.1 grams (0.083 mole) of piperazine (commercially available) and 5.0 grams (0.028 mole) of 2-chloro-5-(trifluoromethyl)pyridine (commercially available) in 75 mL of acetonitrile was heated at reflux during a two-hour period. After this time the reaction mixture was allowed to cool to ambient temperature, and then it was filtered. The filtrate was concentrated under reduced pressure to a residue. The residue was dissolved in 75 mL of methylene chloride and washed with two 50 mL portions of water. The organic layer was dried with sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to a residue. The residue was purified with column chromatography on silica gel using 100% methylene chloride, then 5% methanol in methylene chloride as eluants. The appropriate fractions were combined and concentrated under reduced pressure, yielding 4.5 grams of the subject compound. The NMR spectrum was consistent with the proposed structure.

Source