反应详情

温度

-78 °C

A solution of N-(3,4-dichlorobenzyl)-N-methyl-acetamide (0.83 g, 3.57 mmol) in tetrahydrofuran (15 ml) was cooled to −78° C. and treated dropwise with 7.1 ml (7.1 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran. After 20 min, the mixture was treated dropwise with a solution of dimethyl oxalate (0.63 g, 5.35 mmol) in tetrahydrofuran (3 ml), stirred at −78° C. for 1 h and then at 5° C. for another 45 min. The reaction mixture was then quenched by the addition of 1 N hydrochloric acid and ethyl acetate. The organic phase was washed successively with water, saturated sodium bicarbonate and brine and dried over anhydrous sodium sulfate. Evaporation of the solvent under reduced pressure and chromatography of the residue on silica gel (elution toluene-ethyl acetate, 85:15) gave 0.70 g (61% yield) of the title ester as clear oil. 1HNMR 400 MHz (C6D6) δ (ppm); mixture of rotamers: 2.01 and 2.49 (3H, 2 s, NCH3), 3.43 and 3.5 (3H, 2 s, OCH3), 4.0 and 4.4 (2H, 2 s, NCH2), 6.26 and 6.33 (1H, 2 s, CH), 6.62–7.2 (3H, m, aromatics). Anal. calcd for C13H13Cl2NO4: C, 49.08; H, 4.12; N, 4.40. Found: C, 49.38; H, 4.23; N, 4.30.

1. waitat 5° C. for another 45 min
2. customThe reaction mixture was then quenched by the addition of 1 N hydrochloric acid and ethyl acetate
3. washThe organic phase was washed successively with water, saturated sodium bicarbonate and brine
4. dry with materialdried over anhydrous sodium sulfate
5. customEvaporation of the solvent under reduced pressure and chromatography of the residue on silica gel (elution toluene-ethyl acetate, 85:15)