Reaktion #71662

Reaktionsgleichung

trimethylboroxin

1,1-dimethylethyl 4-{[2-bromo-5-(trifluoromethyl)phenyl]sulfonyl}-1-piperazinecarboxylate

potassium carbonate

trimethylboroxin

→

title compound

Ausbeute 94.0%

1,1-dimethylethyl 4-{[2-methyl-5-(trifluoromethyl)phenyl]sulfonyl}-1-piperazinecarboxylate

Ausbeute 94.0%

Lösungsmittel

1,4-dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture heated at 100° C. for 30 min
2. 2
   Temperaturto cool overnight
3. 3
   EinengenThe mixture was concentrated under vacuum
4. 4
   workup.ADDITIONEtOAc (150 ml) added
5. 5
   Waschenwashed with 200 ml of water
6. 6
   Sonstigedried on a phase separation cartridge
7. 7
   Sonstigeevaporated under vacuum
8. 8
   SonstigeThe crude material (3.1 g) was purified via Biotage (40+M silica column)
9. 9
   SonstigeDesired fractions were collected
10. 10
    Einengenconcentrated under vacuum

Vorschrift

1,1-dimethylethyl 4-{[2-bromo-5-(trifluoromethyl)phenyl]sulfonyl}-1-piperazinecarboxylate (may be prepared as described in Description 28) (2.59 g, 5.47 mmol), potassium carbonate (1.513 g, 10.94 mmol) in 1,4-dioxane (80 ml) were stirred for 5 min then trimethylboroxin (1.523 ml, 10.94 mmol) and Pd(PPh3)4 (0.632 g, 0.547 mmol) were added and the reaction mixture heated at 100° C. for 1.5 h. Further trimethylboroxin (0.5 mL) was added and the mixture heated at 100° C. for 30 min before allowing to cool overnight. The mixture was concentrated under vacuum then EtOAc (150 ml) added, washed with 200 ml of water, dried on a phase separation cartridge and evaporated under vacuum. The crude material (3.1 g) was purified via Biotage (40+M silica column) using a gradient EtOAc/1-hex from 10/90 to 30/70. Desired fractions were collected and concentrated under vacuum to give the title compound (2.1 g).

Quelle