Reaktion #1253197

Reaktionsgleichung

5-Amino-2-(4-[2-fluoroethyl]-3-oxopiperazin-1-yl)fluorobenzene

Pyridine

Benzyl chloroformate

→

5-benzyloxycarbonylamino-2-(4-[2 fluoroethyl]-3-oxopiperazin-1-yl)fluorobenzene

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture cooled to −20°
2. 2
   workup.WAITto rise to 20-25° over 1.5 hours
3. 3
   SonstigeThe solvents are removed
4. 4
   workup.DISSOLUTIONthe residue is dissolved in dichloromethane
5. 5
   Waschenwashed with sodium bicarbonate solution
6. 6
   TrocknenAfter drying over magnesium sulfate and removal of the solvent
7. 7
   Sonstigethe residue is chromatographed (silica
8. 8
   Wascheneluting with a gradient
9. 9
   Temperaturincreasing in polarity from 0 to 5% methanol in dichloromethane)

Vorschrift

5-Amino-2-(4-[2-fluoroethyl]-3-oxopiperazin-1-yl)fluorobenzene (2.6 g) is dissolved in dry dichloromethane (50 ml) under argon. Pyridine (1.03 ml) is added, and the mixture cooled to −20°. Benzyl chloroformate (1.6 ml) is added and the mixture stirred for 10 minutes at −20°, before allowing the temperature to rise to 20-25° over 1.5 hours. The solvents are removed and the residue is dissolved in dichloromethane and washed with sodium bicarbonate solution. After drying over magnesium sulfate and removal of the solvent, the residue is chromatographed (silica, eluting with a gradient increasing in polarity from 0 to 5% methanol in dichloromethane) to give 5-benzyloxycarbonylamino-2-(4-[2 fluoroethyl]-3-oxopiperazin-1-yl)fluorobenzene.

Quelle