Reaktion #48506

Reaktionsgleichung

tert-butyl (3-oxopropyl)carbamate

4-benzylpiperazin-1-amine

hydrochloric acid ethyl acetate

→

title compound

Ausbeute 47.0%

1-(4-Benzylpiperazin-1-yl)tetrahydropyrimidin-2(1H)-one

Ausbeute 47.0%

Lösungsmittel

methanol

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturunder reflux for 3 hours
2. 2
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
3. 3
   workup.DISSOLUTIONAfter the residue was dissolved in methanol (60 mL)
4. 4
   workup.ADDITIONacetic acid (4.1 mL) and sodium triacetoxyborohydride (3.2 g) were added
5. 5
   EinengenThe reaction mixture was concentrated under reduced pressure
6. 6
   Extraktionextracted with dichloromethane
7. 7
   TrocknenThe organic layer was dried over anhydrous sodium sulfate
8. 8
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
9. 9
   SonstigeThe residue obtained
10. 10
    workup.STIRRINGby stirring at room temperature for 5 hours
11. 11
    FiltrationThe precipitate was collected by filtration
12. 12
    Sonstigedried
13. 13
    workup.ADDITIONDBU (14.6 g) and CDI (7.8 g) were added
14. 14
    Temperaturthe mixture was heated
15. 15
    Temperaturunder reflux for 15 hours
16. 16
    EinengenThe reaction mixture was concentrated under reduced pressure
17. 17
    workup.ADDITIONthe residue was diluted with an aqueous sodium bicarbonate solution
18. 18
    Extraktionextracted with dichloromethane
19. 19
    TrocknenThe extract was dried over anhydrous sodium sulfate
20. 20
    workup.DISTILLATIONthe solvent was distilled off under reduced pressure
21. 21
    SonstigeThe residue was purified by basic silica gel column chromatography (ethyl acetate)
22. 22
    Sonstigerecrystallized from diethyl ether

Vorschrift

A solution of tert-butyl (3-oxopropyl)carbamate (4.2 g) and 4-benzylpiperazin-1-amine (4.6 g) in methanol (60 mL) was heated under reflux for 3 hours, and the solvent was distilled off under reduced pressure. After the residue was dissolved in methanol (60 mL), acetic acid (4.1 mL) and sodium triacetoxyborohydride (3.2 g) were added thereto, and the mixture was stirred at room temperature for 15 hours. The reaction mixture was concentrated under reduced pressure, made alkaline with 1N sodium hydroxide and potassium carbonate, and extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. The residue obtained was dissolved in ethyl acetate (10 mL). and then a 4N hydrochloric acid-ethyl acetate solution (100 ml) was slowly added at 0° C., followed by stirring at room temperature for 5 hours. The precipitate was collected by filtration, dried, and then suspended in acetonitrile (200 mL). DBU (14.6 g) and CDI (7.8 g) were added thereto, and the mixture was heated under reflux for 15 hours. The reaction mixture was concentrated under reduced pressure, and the residue was diluted with an aqueous sodium bicarbonate solution and extracted with dichloromethane. The extract was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by basic silica gel column chromatography (ethyl acetate), and recrystallized from diethyl ether to obtain the title compound (3.1 g, 46%) as white crystals.

Quelle