反应详情

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.

1. customat room temperature
2. customThe reaction, which
3. custom(ca. 16 h)
4. customto consume all of the starting 1-(2,4-dichlorophenyl)-2-imidazol-2-ylethan-1-one
5. customThe reaction was quenched by the addition of sat. aq. NH4Cl (˜100 ml)
6. customThe mixture was transferred to a separatory funnel
7. additiondiluted with ethyl acetate (300 ml)
8. customThe aqueous layer was removed
9. washthe organic layer was washed with sat. aq. NH4Cl (3×100 ml), brine (100 ml)
10. dry with materialdried with Na2SO4
11. filtrationAfter filtration and evaporation
12. customthe residue was purified by flash chromatography over silica gel
13. washThe column was eluted
14. customto remove the non-polar methyl 2-phenylthioprop-2-enoate
15. washThe product was eluted with 3% methanol in dichloromethane
16. customAfter drying overnight in vacuo