Reaktion #60132

Reaktionsgleichung

methanol

methyl 2-phenylthioprop-2-enoate

methanol

tert-butoxide

1-(2,4-dichlorophenyl)-2-imidazol-2-ylethan-1-one

methyl 2-phenylthioprop-2-enoate

→

methyl 5-(2,4-dichlorophenyl)-4-imidazol-2-yl-5-oxo-2-phenylthiopentanoate

Ausbeute 71.0%

Lösungsmittel

dichloromethane

dichloromethane

tert-butanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeat room temperature
2. 2
   SonstigeThe reaction, which
3. 3
   Sonstige(ca. 16 h)
4. 4
   Sonstigeto consume all of the starting 1-(2,4-dichlorophenyl)-2-imidazol-2-ylethan-1-one
5. 5
   SonstigeThe reaction was quenched by the addition of sat. aq. NH4Cl (˜100 ml)
6. 6
   SonstigeThe mixture was transferred to a separatory funnel
7. 7
   workup.ADDITIONdiluted with ethyl acetate (300 ml)
8. 8
   SonstigeThe aqueous layer was removed
9. 9
   Waschenthe organic layer was washed with sat. aq. NH4Cl (3×100 ml), brine (100 ml)
10. 10
    Trocknendried with Na2SO4
11. 11
    FiltrationAfter filtration and evaporation
12. 12
    Sonstigethe residue was purified by flash chromatography over silica gel
13. 13
    WaschenThe column was eluted
14. 14
    Sonstigeto remove the non-polar methyl 2-phenylthioprop-2-enoate
15. 15
    WaschenThe product was eluted with 3% methanol in dichloromethane
16. 16
    SonstigeAfter drying overnight in vacuo

Vorschrift

A solution (1 M) of tert-butoxide in tert-butanol (54.9 ml) was added to a stirred solution of 1-(2,4-dichlorophenyl)-2-imidazol-2-ylethan-1-one (0.11 M) and methyl 2-phenylthioprop-2-enoate (0.14 M) dissolved in dichloromethane (300 ml) and methanol (200 ml) at room temperature. The reaction, which developed a dark color, was typically stirred overnight (ca. 16 h) under argon. The reaction was monitored by TLC using 5% methanol in dichloromethane as the solvent system. Additional methyl 2-phenylthioprop-2-enoate was added as needed to consume all of the starting 1-(2,4-dichlorophenyl)-2-imidazol-2-ylethan-1-one. The reaction was quenched by the addition of sat. aq. NH4Cl (˜100 ml). The mixture was transferred to a separatory funnel and diluted with ethyl acetate (300 ml). The aqueous layer was removed and the organic layer was washed with sat. aq. NH4Cl (3×100 ml), brine (100 ml), and dried with Na2SO4. After filtration and evaporation, the residue was purified by flash chromatography over silica gel. The column was eluted starting with 100% dichloromethane to remove the non-polar methyl 2-phenylthioprop-2-enoate. The product was eluted with 3% methanol in dichloromethane. After drying overnight in vacuo, methyl 5-(2,4-dichlorophenyl)-4-imidazol-2-yl-5-oxo-2-phenylthiopentanoate as a deep red glass was obtained in 71% yield. A further 10% yield of product could be obtained by resubmitting side product contaminated fractions to a second purification by flash chromatography.

Quelle