反应 #2467967

反应方程式

Methyl 4-hydroxy-5-(methoxycarbonyl)thiophene-2-carboxylate

sulfuric acid

nitric acid

→

semi-solid

收率 20.0%

Methyl 4-hydroxy-5-(methoxycarbonyl)-3-nitrothiophene-2-carboxylate

收率 20.0%

溶剂

water

反应条件

后处理

1. 1
   workup.ADDITIONThe mixture was poured into ice
2. 2
   萃取extracted with ethyl acetate (3×100 mL)
3. 3
   洗涤The combined organic layer was washed with water, brine
4. 4
   干燥dried over sodium sulfate
5. 5
   过滤The solution was filtered
6. 6
   其他evaporated the solvent
7. 7
   其他The residue was chromatographed over silica gel column

实验过程

Methyl 4-hydroxy-5-(methoxycarbonyl)thiophene-2-carboxylate (5 g, 23.14 mmol) was added slowly for 15 min at 0 to −5° C. to concentrated sulfuric acid (25 mL). Then concentrated nitric acid (3.2 mL, 70%, 34.7 mmol) was added to the above reaction mixture for 10 min and stirred at the same temperature for 1 h. The mixture was poured into ice cooled water and extracted with ethyl acetate (3×100 mL). 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 chloroform-methanol (95:5) as eluents to give the product as a yellow color semi-solid (1.2 g, 20%).

来源