反应详情

To a solution of 2-bromo-4-bromomethyl-benzoic acid methyl ester (0.50g, 1.62 mmol) and 1-benzyl-1H-indole-3-carbaldehyde oxime (0.43 g, 1.70 mmol) in acetone (50 mL) was added cesium carbonate (2.12 g, 6.49 mmol). The mixture was heated to reflux for 6 hours and allowed to cool back to room temperature. The mixture was partitioned between ethyl acetate and brine and the layers were then separated. The aqueous layer was extracted with one additional portion of ethyl acetate. The organics were combined, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude material was purified by flash chromatography through silica gel using ethyl acetate/hexanes (0/100 gradient to 20/80) to give an off-white solid. This solid was recrystallized one time from ethyl acetate/hexanes (1/6) to give 4-[({[(1E)-(1-benzyl-1H-indol-3-yl)methylidene]amino}oxy)methyl]-2-bromobenzoic acid methyl ester (0.26 g, 34%) as off-white crystals. 1H NMR (400 MHz, CDCl3); δ 8.12 (s, 1H), 7.76 (m, 4H), 7.68 (s, 1H), 7.35 (d, 1H), 7.28 (m, 3H), 7.23 (m, 2H), 7.11 (d, 2H), 5.33 (s, 2H), 5.27 (s, 2H), 3.90 (s, 3H).

1. temperatureThe mixture was heated
2. temperatureto reflux for 6 hours
3. customThe mixture was partitioned between ethyl acetate and brine
4. customthe layers were then separated
5. extractionThe aqueous layer was extracted with one additional portion of ethyl acetate
6. dry with materialdried over anhydrous magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customThe crude material was purified by flash chromatography through silica gel
10. customto give an off-white solid
11. customThis solid was recrystallized one time from ethyl acetate/hexanes (1/6)