Lithium Hexamethyldisilazide → Ethyl 3-(2-fluoro-3,6-dimethoxyphenyl)-2-(3-methoxyphenyl)-3-oxopropanoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a mixture of 2-fluoro-3,6-dimethoxybenzoic acid (4.8 g, 24 mmol) in anhydrous dichloromethane (75 mL) at 0° C., SOCl2 (14.2 g, 120 mmol) was slowly added followed by DMF (0.1 mL). The resulting mixture was stirred at room temperature for 2 h and concentrated in vacuo to give 2-fluoro-3,6-dimethoxybenzoyl chloride (5.2 g). To a solution of ethyl 2-(3-methoxyphenyl)acetate (4.7 g, 24 mmol) in anhydrous THF (40 mL) at −78° C., LiHMDS (1.0 M in THF, 36 mL) was added dropwise. The resulting solution was stirred at −78° C. for 30 min and a solution of 2-fluoro-3,6-dimethoxybenzoyl chloride (5.2 g, 24 mmol) in anhydrous THF (60 ml) was added dropwise. The reaction mixture was stirred for additional 2 h at −78° C. and quenched with saturated NH4Cl. The mixture was extracted with ethyl acetate (3×200 mL). The combined organic layers were dried (Na2SO4) and concentrated under reduced pressure to afford the title compound (7.8 g).

Herkunft & Nachweise