反应详情

3-(3,4-Dimethoxy-phenyl)-acrylic acid (compound of Example 2, Method A, Step 1; 3.5 g, 16.80 mmol) was dissolved in dry DMF (35 mL). 1,1′-Carbonyldiimidazole (CDI) (3.0 g, 18.48 mmol) was added and the reaction mixture was stirred at room temperature. At the end of 3 h, N-hydroxy-butyramidine (1.88 g, 18.48 mmol) was added and the reaction mixture was stirred at room temperature for 8 h. After completion of the reaction, additional CDI (2.99 g, 18.48 mmol) was added and the reaction mixture was refluxed at 110° C. to 120° C. for 7 h to effect cyclodehydration. DMF was evaporated and the residue obtained was cooled to room temperature followed by addition of water (20 mL). The resulting mixture was extracted with ethyl acetate (3×15 mL). The combined organic layers were washed with water (2×10 mL) and brine (10 mL). The organic phase obtained was dried over anhydrous sodium sulfate and concentrated to afford the title compound.

1. stirringthe reaction mixture was stirred at room temperature for 8 h
2. additionwas added
3. temperaturethe reaction mixture was refluxed at 110° C. to 120° C. for 7 h
4. customDMF was evaporated
5. customthe residue obtained
6. temperaturewas cooled to room temperature
7. extractionThe resulting mixture was extracted with ethyl acetate (3×15 mL)
8. washThe combined organic layers were washed with water (2×10 mL) and brine (10 mL)
9. customThe organic phase obtained
10. dry with materialwas dried over anhydrous sodium sulfate
11. concentrationconcentrated