反应详情

Hydroxylamine hydrochloride (0.69 g.; 0.01 mol.) was added to a mixture of ethyl-2-(4'-nitrobenzoyl)-3-dimethylaminopropenoate (2.93 g.; 0.01 mol.) and anhydrous sodium acetate (0.82 g.; 0.01 mol.) in 50 ml. of tetrahydrofuran and 25 ml. of methanol. The resultant mixture was stirred at 25° C. for 16 hours until the reaction was complete. The reaction mixture was filtered and the solvent removed from the filtrate by concentration in vacuo. The residue was dissolved in chloroform, extracted with water, dried over magnesium sulfate and then concentrated in vacuo. Recrystallization with ethanol yielded ethyl-5-(4'-nitrophenyl)-4-isoxazolecarboxylate as a white solid (1.2 g.; 45.8% yield) having a melting point of 73°-76° C. and the following analysis:

1. filtrationThe reaction mixture was filtered
2. customthe solvent removed from the filtrate by concentration in vacuo
3. dissolutionThe residue was dissolved in chloroform
4. extractionextracted with water
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated in vacuo
7. customRecrystallization with ethanol