反应详情

温度

0 °C

A solution of 3-(3-fluoro-phenyl)-3-oxo-propionic acid ethyl ester (4.85 mmol) in acetic acid (1.90 mmol) is cooled to 10° C. and a solution of sodium nitrite (5.63 mmol) in water (0.68 mL) is added dropwise. The mixture is allowed to reach RT, stirred for 2 h, poured into water (10 mL) and cooled to 0° C. The precipitate is filtered off and dried by azeotropic removal of water with toluene to give crude 3-(3-fluoro-phenyl)-2-hydroxyimino-3-oxo-propionic acid ethyl ester which is dissolved in a mixture of acetic anhydride (1.38 mL) and acetic acid (1.80 mL). Sodium acetate (0.30 mmol), HgCl2 (0.01 mmol) and zinc powder (14.6 mmol) are added successively. The mixture is stirred under reflux for 1 h, cooled to RT and filtered and the residue is washed with ether. The filtrate is washed three times with water and once with aq. K2CO3 solution (1.0 M). The organic layer is dried over MgSO4 and concentrated in vacuo to give the desired crude product which is purified by FC (heptane to heptane/EtOAc 3/7). LC-MS: tR=0.82 min; [M+H]+=268.1.

1. customto reach RT
2. filtrationThe precipitate is filtered off
3. dry with materialdried by azeotropic removal of water with toluene