3,5-二氟-4-甲酰基苯甲酸甲酯

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of methyl 3,5-difluorobenzoate (1 gm, 5.8 mmol) in dry tetrahydrofuran (20 mL), lithium diisopropylamide (0.621 gm, 5.8 mmol, 15% solution in tetrahydrofuran and heptane) was added at −78° C. The resulting reaction mixture was stirred for about 1 hour. Dimethylformamide (0.51 g, 6.9 mmol) was added drop wise to the reaction mixture and stirring was continued for about 3 hours at −78° C. The reaction was warm up to room temperature. Saturated aqueous ammonium chloride solution (20 mL) was added to quench the reaction mass. The aqueous phase was extracted with ethyl acetate (3×50 mL) and the combined organic layer dried over anhydrous sodium sulfate, filtered and concentrated. The crude product was purified by column chromatography over silica gel (100-200) using ethyl acetate/hexane gradient elution to afford methyl 3,5-difluoro-4-formylbenzoate (0.5 gm, 31.25%). The resulting reaction mixture stirring was continued for about 3 hours at −78° C to quench the reaction mass The aqueous phase was extracted with ethyl acetate (3×50 mL) the combined organic layer dried over anhydrous sodium sulfate filtered concentrated The crude product was purified by column chromatography over silica gel (100-200) ethyl acetate/hexane gradient elution

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of methyl 3,5-difluorobenzoate (1 gm, 5.8 mmol) in dry tetrahydrofuran (20 mL), lithium diisopropylamide (0.621 gm, 5.8 mmol, 15% solution in tetrahydrofuran and heptane) was added at −78° C. The resulting reaction mixture was stirred for about 1 hour. Dimethylformamide (0.51 g, 6.9 mmol) was added drop wise to the reaction mixture and stirring was continued for about 3 hours at −78° C. The reaction was warm up to room temperature. Saturated aqueous ammonium chloride solution (20 mL) was added to quench the reaction mass. The aqueous phase was extracted with ethyl acetate (3×50 mL) and the combined organic layer dried over anhydrous sodium sulfate, filtered and concentrated. The crude product was purified by column chromatography over silica gel (100-200) using ethyl acetate/hexane gradient elution to afford methyl 3,5-difluoro-4-formylbenzoate (0.5 gm, 31.25%). The resulting reaction mixture stirring was continued for about 3 hours at −78° C to quench the reaction mass The aqueous phase was extracted with ethyl acetate (3×50 mL) the combined organic layer dried over anhydrous sodium sulfate filtered concentrated The crude product was purified by column chromatography over silica gel (100-200) ethyl acetate/hexane gradient elution

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of methyl 3,5-difluorobenzoate (1 gm, 5.8 mmol) in dry tetrahydrofuran (20 mL), lithium diisopropylamide (0.621 gm, 5.8 mmol, 15% solution in tetrahydrofuran and heptane) was added at −78° C. The resulting reaction mixture was stirred for about 1 hour. Dimethylformamide (0.51 g, 6.9 mmol) was added drop wise to the reaction mixture and stirring was continued for about 3 hours at −78° C. The reaction was warm up to room temperature. Saturated aqueous ammonium chloride solution (20 mL) was added to quench the reaction mass. The aqueous phase was extracted with ethyl acetate (3×50 mL) and the combined organic layer dried over anhydrous sodium sulfate, filtered and concentrated. The crude product was purified by column chromatography over silica gel (100-200) using ethyl acetate/hexane gradient elution to afford methyl 3,5-difluoro-4-formylbenzoate (0.5 gm, 31.25%). The resulting reaction mixture stirring was continued for about 3 hours at −78° C to quench the reaction mass The aqueous phase was extracted with ethyl acetate (3×50 mL) the combined organic layer dried over anhydrous sodium sulfate filtered concentrated The crude product was purified by column chromatography over silica gel (100-200) ethyl acetate/hexane gradient elution