反应详情

To a suspension of acetoxy-(4-methoxy-phenyl)-acetic acid (79a) (2.78 g, 12.40 mmol) in CH2Cl2 (50 mL), was added 2.0 M oxalyl chloride in CH2Cl2 (9.30 mL, 18.60 mmol), followed by 10 drops of DMF. The mixture was stirred at ambient temperature for one hour, concentrated and further dried under high vacuum. It was re-dissolved in CH2Cl2 (50 mL); to this solution was added 5-amino-3-methylisoxazole (1.34 g, 13.66 mmol), followed by Et3N (2.60 mL, 18.60 mmol). After stirring at ambient temperature overnight, the mixture was concentrated in vacuo and purified by flash column chromatography eluting with 1:1 EtOAc and hexanes to provide 2.70 g yellow solid as the intermediate 79b. 1H NMR (300 MHz, CDCl3) δ 8.56 (s, 1H), 7.36 (d, 2H, J=8.67 Hz), 6.90 (d, 2H, J=8.67 Hz), 6.24 (s, 1H), 6.17 (s, 1H), 3.80 (s, 3H), 2.25 (s, 3H), 2.22 (s, 3H). LCMS (ESI—) [M−H]/z Calc'd 303, found 303.

1. concentrationconcentrated
2. customfurther dried under high vacuum
3. dissolutionIt was re-dissolved in CH2Cl2 (50 mL)
4. stirringAfter stirring at ambient temperature overnight
5. concentrationthe mixture was concentrated in vacuo
6. custompurified by flash column chromatography
7. washeluting with 1:1 EtOAc and hexanes