反应详情

To a solution of benzamidine 207 (1.44 g, 12 mmol) and potassium carbonate (4.1 g, 30 mmol) in anhydrous DMF (25 mL) is slowly added a solution of 3-bromo-1,1-dimethoxy-propan-2-one 206 (1.97 g, 10 mmol) in anhydrous DMF (10 mL) over 30 min. The mixture is then heated at 50–60° C. for 2 h. After cooling to room temperature, ethyl acetate (100 mL) and water (100 mL) were added. The organic phase is separated and the aqueous phase is extracted with ethyl acetate twice and the combined organic phase is washed with water (3×20 mL) and brine. Removal of solvents under reduced pressure and purification of the residue by column chromatography affords the desired product as a white solid. Yield: 2.08 g; LC-MS (MH+): 219. 1H NMR (300 MHz, CDCl3) δ 7.88–7.85 (m, 2H), 7.37–7.46 (m, 4H), 5.49 (s, 1H), 3.36 (s, 6H).

1. temperatureThe mixture is then heated at 50–60° C. for 2 h
2. customThe organic phase is separated
3. extractionthe aqueous phase is extracted with ethyl acetate twice
4. washthe combined organic phase is washed with water (3×20 mL) and brine
5. customRemoval of solvents
6. customunder reduced pressure and purification of the residue by column chromatography