Reaktion #1253194

Reaktionsgleichung

1-t-Butoxycarbonyl-3-oxopiperazine

potassium t-butoxide

1-(4-methylphenylsulfonyloxy)-2-fluoroethane

→

1-t-butoxycarbonyl-4-(2-fluoroethyl)-3-oxopiperazine

Lösungsmittel

DMF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITcontinued at the same temperature for 24 hours
3. 3
   SonstigeThe solvent is removed
4. 4
   Sonstigethe residue partitioned between ethyl acetate and water
5. 5
   WaschenThe organic phase is washed with water
6. 6
   Einengenconcentrated
7. 7
   workup.DISSOLUTIONThe residue is dissolved in isopropanol
8. 8
   workup.ADDITIONdiluted with iso-hexane forming a precipitate which
9. 9
   Sonstigeis removed by filtration
10. 10
    SonstigeThe mixture is chromatographed (silica
11. 11
    Wascheneluting with
12. 12
    Temperatura gradient increasing in polarity from 0 to 50% isopropanol in iso-hexane)

Vorschrift

1-t-Butoxycarbonyl-3-oxopiperazine (21.6 g) is dissolved in dry DMF (500 ml) and potassium t-butoxide (24.2 g) is added. The mixture is stirred at 20-25° for 30 minutes, then 1-(4-methylphenylsulfonyloxy)-2-fluoroethane (J. Med. Chem., 23(9), 985-90 (1980), 25.9 g) is added and stirring continued at the same temperature for 24 hours. The solvent is removed and the residue partitioned between ethyl acetate and water. The organic phase is washed with water and concentrated. The residue is dissolved in isopropanol and diluted with iso-hexane forming a precipitate which is removed by filtration. The mixture is chromatographed (silica; eluting with a gradient increasing in polarity from 0 to 50% isopropanol in iso-hexane) to give 1-t-butoxycarbonyl-4-(2-fluoroethyl)-3-oxopiperazine.

Quelle