Reaktion #2341

Reaktionsgleichung

diethyl azodicarboxylate

Methyl-4-hydroxy-3-vinylbutyrate

4-[4-(4-pyridyl)piperazin-1-yl]phenol

triphenylphosphine

→

ammonium hydroxide

methyl 4-[4-[4-(4-pyridyl)piperazin-1-yl]-phenoxy]-3-vinylbutyrate

Ausbeute 19.6%

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewas obtained
2. 2
   workup.STIRRINGthe mixture stirred for 4 hours
3. 3
   SonstigeThe solid which had precipitated during the reaction
4. 4
   Filtrationwas filtered off
5. 5
   SonstigeThe filtrate was evaporated
6. 6
   workup.ADDITIONthe residue treated with ethyl acetate (20 ml)
7. 7
   Filtrationfiltered
8. 8
   ExtraktionThe filtrate was extracted with 2N hydrochloric acid (2×10 ml)
9. 9
   Sonstigethe aqueous layer separated
10. 10
    ExtraktionThe precipitate was extracted twice into ethyl acetate
11. 11
    Filtrationthe combined extracts filtered through phase
12. 12
    Sonstigeseparating paper
13. 13
    Sonstigeevaporated
14. 14
    SonstigeThe residue was purified by flash chromatography on silica gel
15. 15
    Wascheneluting with methanol/dichloromethane/0.89 S

Vorschrift

To a stirred suspension of 4-[4-(4-pyridyl)piperazin-1-yl]phenol (1.98 g) in dichloromethane (30 ml) at 15° C. was added triphenylphosphine (2.04 g) followed by dropwise addition of diethyl azodicarboxylate (1.35 g). The mixture was stirred until complete solution was obtained. Methyl-4-hydroxy-3-vinylbutyrate (1.12 g) was added dropwise and the mixture stirred for 4 hours. The solid which had precipitated during the reaction was the starting phenol and was filtered off. The filtrate was evaporated and the residue treated with ethyl acetate (20 ml) and filtered. The filtrate was extracted with 2N hydrochloric acid (2×10 ml) and the aqueous layer separated and basified with 0.89 S.G. ammonium hydroxide. The precipitate was extracted twice into ethyl acetate and the combined extracts filtered through phase separating paper and evaporated. The residue was purified by flash chromatography on silica gel, eluting with methanol/dichloromethane/0.89 S. G. ammonium hydroxide v:v:v 7.5/92.5/0.75 to give RS methyl 4-[4-[4-(4-pyridyl)piperazin-1-yl]-phenoxy]-3-vinylbutyrate (0.29 g); NMR(CDCl3) δ 8.3(2H,d), 6.88(4H,m), 6.70(2H,d), 5.85(1H,m), 5.20(2H,m), 3.90(2H,m), 3.67(3H,s), 3.48(2H,m), 3.18(2H,m), 3.06(1H,m), 2.68(1H,m), 2.47(1H,m), 1.80(1H,br); m/e 382 (M+H)+.

Quelle