反应详情

A reaction mixture consisting of ethyl 5-acetylisoxazole-3-carboxylate (2.53 g, 13.8 mmol), ethylene glycol (1.29 g, 20.7 mmol) and p-TsOH (0.13 g, 0.69 mmol) in benzene (50 mL) was refluxed with the Dean-Stark adapter for 24 hours (scheme 59). Most of the solvent was removed under reduced pressure and the residue was partitioned between saturated NaHCO3 and EtOAc. Organic layer was collected, washed with brine, water, and dried over MgSO4. Evaporation of the dried extract under reduced pressure afforded the title compound as an oil (3.14 g, 100% yield), which was used for next step without further purification. 1H NMR (DMSO-d6) δ (ppm): 6.89 (s, 1H), 4.35 (q, J=7.2 Hz, 2H), 4.07-4.01 (m, 2H), 4.01-3.94 (m, 2H), 1.70 (s, 3H), 1.32 (t, J=7.0 Hz, 3H). MS (m/z): 227.21 (calc) 228.1 (MH+) (found).

1. temperaturewas refluxed with the Dean-Stark adapter for 24 hours (scheme 59)
2. customMost of the solvent was removed under reduced pressure
3. customthe residue was partitioned between saturated NaHCO3 and EtOAc
4. customOrganic layer was collected
5. washwashed with brine, water
6. dry with materialdried over MgSO4
7. customEvaporation of the dried
8. extractionextract under reduced pressure