反応 #2467967

反応方程式

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

sulfuric acid

nitric acid

→

semi-solid

収率 20.0%

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

収率 20.0%

溶媒

water

反応条件

後処理

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

実験手順

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%).

出典