1,1'-Carbonyldiimidazole → 5-[2-(4-Methoxy-3-nitro-phenyl)-vinyl]-3-propyl-[1,2,4]oxadiazole

Beteiligte Stoffe

Reaktionsschritte

3-(4-Methoxy-3-nitro-phenyl)-acrylic acid (compound of Example 6; 0.95 g, 4.25 mmol) was dissolved in DMF (15 mL) to which CDI (0.82 g, 5.10 mmol) was added and the reaction mixture was stirred at room temperature. After 45 min, N-hydroxy-butyramidine (0.52 g, 5.10 mmol) was added. The reaction mixture was stirred at room temperature for about 16-18 h. After completion of the reaction, additional CDI (0.82 g, 5.10 mmol) was added and the reaction mixture was refluxed at 110° C. to 120° C. for 6 h to effect cyclodehydration. DMF was evaporated and the reaction mixture was cooled to room temperature. Water (10 mL) was added to the reaction mixture followed by extraction with ethyl acetate (2×10 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 obtain a crude product, which was purified by column chromatography (silica gel, 0.25% ethyl acetate in petroleum ether) to afford the title compound.

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