反应详情

To a solution of methyl 4-(dimethoxymethyl)-3-phenylisoxazole-5-carboxylate, 12-B, (144 mg, 0.519 mmol) in acetone (3 mL) at rt was added Jones' Reagent (0.539 mL, 0.727 mmol) and the resulting mixture was allowed to stir at rt for 1 hr. Three additional aliquots of Jones' Reagent (0.539 mL, 0.727 mmol) were added portion wise over 1 hr and stirring was continued at rt for 2 hr. At this time, the reaction mixture was partitioned between EtOAc (30 mL) and 2% NaHSO3 solution (30 mL). The organic layer was washed with brine (20 mL), dried (MgSO4) and concentrated to afford 5-(methoxycarbonyl)-3-phenylisoxazole-4-carboxylic acid (108 mg, 0.437 mmol, 84% yield) as a light yellow solid. HPLC retention time=1.30 minutes (PHENOMENEX® Luna 4.6×30 mm S-5 ODS column) eluting with 10-90% aqueous methanol+0.1% TFA over a 2 minute gradient. MS: (M+H)=248.13. 1H NMR (400 MHz, chloroform-d) δ ppm 4.16 (s, 3H), 7.50 (m, 3H), 7.66 (dd, J=8.2, 1.4 Hz, 2H).

1. stirringstirring
2. waitwas continued at rt for 2 hr
3. customAt this time, the reaction mixture was partitioned between EtOAc (30 mL) and 2% NaHSO3 solution (30 mL)
4. washThe organic layer was washed with brine (20 mL)
5. dry with materialdried (MgSO4)
6. concentrationconcentrated