反应详情

A solution of imidazole (5.0 g, 0.074 mol), ethyl 2-bromopropanoate (7.6 ml, 0.06 mol) and K2CO3 (11.2 g, 0.08 mol) in DMF (120 ml) was heated at 90° C. for 2 h. After this time the solution was cooled to room temperature, filtered and the filtrate diluted with EtOAc (200 ml). The mixture was washed with water (2×20 ml) and the organic phase separated. The combined aqueous layers were washed with EtOAc (200 ml) and the combined organic layers washed with brine (200 ml). The organic layer was separated, dried (Na2SO4) and evaporated. The residue was chromatographed on silica, eluting with CH2Cl2 :MeOH (95:5), to afford the ester (1.1 g, 9%) as a pale yellow oil. 1H NMR (250 MHz, CDCl3) δ 1.26 (3H, t, J=7.1 Hz), 1.75 (3H, d, J=7.3 Hz), 4.20 (2H, q, J=7.1 Hz), 4.85 (1H, q, J=7.3 Hz), 7.02-7.04 (1H, m), 7.08-7.10 (1H, m), 7.58 (1H, s).

1. filtrationfiltered
2. additionthe filtrate diluted with EtOAc (200 ml)
3. washThe mixture was washed with water (2×20 ml)
4. customthe organic phase separated
5. washThe combined aqueous layers were washed with EtOAc (200 ml)
6. washthe combined organic layers washed with brine (200 ml)
7. customThe organic layer was separated
8. dry with materialdried (Na2SO4)
9. customevaporated
10. customThe residue was chromatographed on silica
11. washeluting with CH2Cl2 :MeOH (95:5)