Ammonium Chloride → 1,4-Dibenzyl-2-ethenylpiperazine

Temperatur

-78 °C

After a solution of 1,4-dibenzyl-2-(ethoxycarbonyl)piperazine (6.76 g) in methylene chloride (250 ml) was cooled to −78° C., diisobutylaluminum hydride (a 1.0 mol/l hexane solution, 39.90 ml) was added dropwise and the mixture was stirred at −78° C. for 2 hours. A saturated aqueous solution of ammonium chloride and methylene chloride were added to the reaction mixture. The water layer was extracted three times. The organic layers were combined, washed with distilled water and dried over anhydrous sodium sulfate. The residue obtained by distilling off the solvent under reduced pressure was provided for the subsequent reaction without purification. After cooling a tetrahydrofuran solution (150 ml) of methyltriphenylphosphonium iodide (8.07 g) to −78° C., n-butyl lithium (a 1.52 mole hexane solution, 13.14 ml) was added dropwise and the mixture was stirred at −78° C. for 2 hours. A solution of the residue, which residue had been obtained above, in tetrahydrofuran was then added. The reaction mixture was heated from −78° C. to 0° C. while stirring for 4 hours and then, a saturated aqueous solution of ammonium chloride was added to terminate the reaction. Diethyl ether was added and the water layer was extracted three times. The organic layers were combined, washed with saturated aqueous NaCl solution and dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent under reduced pressure was subjected to chromatography on a silica gel column (methanol:methylene chloride=1:50), whereby the title compound (3.22 g) was obtained as a pale yellow oil.

1. extractionThe water layer was extracted three times
2. washwashed with distilled water
3. dry with materialdried over anhydrous sodium sulfate
4. customThe residue obtained
5. distillationby distilling off the solvent under reduced pressure
6. customwas provided for the subsequent reaction without purification
7. stirringthe mixture was stirred at −78° C. for 2 hours
8. additionwas then added
9. temperatureThe reaction mixture was heated from −78° C. to 0° C.
10. stirringwhile stirring for 4 hours
11. customto terminate
12. customthe reaction
13. extractionthe water layer was extracted three times
14. washwashed with saturated aqueous NaCl solution
15. dry with materialdried over anhydrous magnesium sulfate
16. customThe residue obtained
17. distillationby distilling off the solvent under reduced pressure
18. customwas obtained as a pale yellow oil

ORD-Eintrag

ord-e2b7a2f4877e44a7be4439fa03d56cbd

Quelldatensatz

uspto-grants-2004_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06747023B1