반응 #2467989

반응 방정식

2-aminothiophene-3-carboxamide

sodium nitrite

→

solid

수율 18.5%

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

수율 18.5%

용매

sulfuric acid

sulfuric acid

반응 조건

후처리

1. 1
   workup.ADDITIONwhile adding
2. 2
   기타should keep between −5-0° C.
3. 3
   workup.ADDITIONAfter addition
4. 4
   workup.ADDITIONThe mixture was poured
5. 5
   기타into crushed ice slowly
6. 6
   workup.STIRRINGwith stirring for 15 min
7. 7
   workup.STIRRINGstirred at the same temperature for 15 min
8. 8
   추출The solution was extracted with ethyl acetate (4×200 mL)
9. 9
   세척the combined EtOAc layer was washed with water, brine
10. 10
    건조dried over sodium sulfate
11. 11
    여과The solution was filtered
12. 12
    기타evaporated the solvent
13. 13
    기타The residue was chromatographed over silica gel column

실험 절차

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)−.

출처