反応 #2467989

反応方程式

2-aminothiophene-3-carboxamide

sodium nitrite

→

solid

収率 18.5%

3H-Thiopheno[2,3-d]1,2,3-triazin-4-one

収率 18.5%

溶媒

sulfuric acid

sulfuric acid

反応条件

後処理

1. 1
   workup.ADDITIONwhile adding
2. 2
   その他should keep between −5-0° C.
3. 3
   workup.ADDITIONAfter addition
4. 4
   workup.ADDITIONThe mixture was poured
5. 5
   その他into crushed ice slowly
6. 6
   workup.STIRRINGwith stirring for 15 min
7. 7
   workup.STIRRINGstirred at the same temperature for 15 min
8. 8
   抽出The solution was extracted with ethyl acetate (4×200 mL)
9. 9
   洗浄the combined EtOAc layer was washed with water, brine
10. 10
    乾燥dried over sodium sulfate
11. 11
    ろ過The solution was filtered
12. 12
    その他evaporated the solvent
13. 13
    その他The residue was chromatographed over silica gel column

実験手順

To an ice cold solution (0° C.) of 2-aminothiophene-3-carboxamide (5 g, 35.21 mmol) in concentrated sulfuric acid (40 mL) was added a cold (0° C.) solution of sodium nitrite (2.5 g, 35.21 mmol) in concentrated sulfuric acid (30 mL) for 30 min (while adding, the temperature should keep between −5-0° C.). After addition, the mixture was stirred at the same temperature (0° C.) for 3 h. The mixture was poured into crushed ice slowly with stirring for 15 min and stirred at the same temperature for 15 min. The solution was extracted with ethyl acetate (4×200 mL) and the combined EtOAc 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 pale red color solid (1.0 g, 18%), mp 175-176° C. 1H NMR (400 MHz, DMSO-d6): δ 15.18 (1H, s), 8.16 (1H, d, J=5.6 Hz), 7.64 (1H, d, J=5.6 Hz); 13C NMR (100 MHz, DMSO-d6): δ 159.1, 153.8, 132.0, 126.1, 121.2; LC-MS (negative ion mode): m/z 152 (M−H)−.

出典