反应详情

To an ice cold (0-10° C.) solution of methyl 5-methylselenophene-2-carboxylate (5.4 g, 26.6 mmol) in acetic anhydride (15 mL) was added an ice cold mixture of nitric acid (5.5 mL, 61.1 mmol, 70%) and acetic anhydride (10 mL) for 10 min. The reaction mixture was slowly allowed to room temperature (rt) for 1 h and stirred at rt for 16 h. The mixture was poured into ice cold water and stirred for 10 min. The solution was extracted with chloroform (3×100 mL) and the combined organic layer was washed with water, brine and dried over sodium sulfate. The solution was filtered and evaporated the solvent. The residue was chromatographed over silica gel column using hexane-ethyl acetate (90:10) as eluents to give the product as an pale yellow color solid (2.3 g, 35%), mp 90-92° C. 1H NMR (400 MHz, CDCl3): δ 8.54 (1H, s, H-3), 3.90 (3H, s, —COOCH3), 2.90 (3H, s, —CH3).

1. customwas slowly allowed to room temperature
2. custom(rt)
3. customfor 1 h
4. additionThe mixture was poured into ice cold water
5. stirringstirred for 10 min
6. extractionThe solution was extracted with chloroform (3×100 mL)
7. washthe combined organic layer was washed with water, brine
8. dry with materialdried over sodium sulfate
9. filtrationThe solution was filtered
10. customevaporated the solvent
11. customThe residue was chromatographed over silica gel column