Reaktion #2467967

Reaktionsgleichung

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

sulfuric acid

nitric acid

→

semi-solid

Ausbeute 20.0%

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

Ausbeute 20.0%

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONThe mixture was poured into ice
2. 2
   Extraktionextracted with ethyl acetate (3×100 mL)
3. 3
   WaschenThe combined organic layer was washed with water, brine
4. 4
   Trocknendried over sodium sulfate
5. 5
   FiltrationThe solution was filtered
6. 6
   Sonstigeevaporated the solvent
7. 7
   SonstigeThe residue was chromatographed over silica gel column

Vorschrift

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%).

Quelle