反应详情

3-(3,4-Dimethoxy-phenyl)-acrylic acid (compound of Example 2, Method A, Step 1; 4 g, 19.21 mmol) was dissolved in DMF (30 mL) to which 1,1′-Carbonyldiimidazole (CDI) (4.04 g, 24.97 mmol) was added and the reaction mixture was stirred at room temperature. At the end of 3 h, N-hydroxy-propionamidine (2.03 g, 23.05 mmol) was added and the reaction mixture was stirred at room temperature for 8 h. After completion of the reaction, additional CDI (4.04 g, 24.97 mmol) was added and the reaction mixture was refluxed at 110° C. to 120° C. for 8 h to effect cyclodehydration. After evaporation of DMF, the residue obtained was cooled to room temperature followed by addition of water (25 mL) and extracted with ethyl acetate (3×15 mL). The combined organic layers were washed with water (2×10 mL) and brine (10 mL), dried over anhydrous sodium sulfate and concentrated to afford the title compound.

1. additionwas added
2. stirringthe reaction mixture was stirred at room temperature for 8 h
3. additionwas added
4. temperaturethe reaction mixture was refluxed at 110° C. to 120° C. for 8 h
5. customAfter evaporation of DMF
6. customthe residue obtained
7. temperaturewas cooled to room temperature
8. extractionextracted with ethyl acetate (3×15 mL)
9. washThe combined organic layers were washed with water (2×10 mL) and brine (10 mL)
10. dry with materialdried over anhydrous sodium sulfate
11. concentrationconcentrated