反应详情

A mixture of 3-methylisoxazole-5-carboxylic acid (0.63 g, 5.0 mmol), cesium carbonate (0.8 g, 2.45 mmol) and methanol was stirred for 30 minutes. The solvent was removed in vacuo and the residue was dried in high vacuum for 1 hour. The residue was suspended in DMF (30 ml) and 2-chloromethyl-4-isopropyl-6-methoxysaccharin (1.0 g, 3.3 mmol) was added. The mixture was stirred at room temperature for 19 hours and was poured into water. The mixture was extracted with ethyl acetate/ether (4/1, 300 ml) and the organic layer was separated and wash with water, then brine. The solvent was removed in vacuo and the residue was purified by flash chromatography (30% ethyl acetate/hexanes) to afford 1.1 g (85%) of 4-isopropyl-6-methoxy-2-saccharinylmethyl 3-methylisoxazole-5-carboxylate as a white powder, m.p. 157°-158° C.

1. customThe solvent was removed in vacuo
2. customthe residue was dried in high vacuum for 1 hour
3. stirringThe mixture was stirred at room temperature for 19 hours
4. extractionThe mixture was extracted with ethyl acetate/ether (4/1, 300 ml)
5. customthe organic layer was separated
6. washwash with water
7. customThe solvent was removed in vacuo
8. customthe residue was purified by flash chromatography (30% ethyl acetate/hexanes)