تفاعل #2467989

معادلة التفاعل

2-aminothiophene-3-carboxamide

sodium nitrite

→

solid

المردود 18.5%

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

المردود 18.5%

المذيبات

sulfuric acid

sulfuric acid

ظروف التفاعل

المعالجة

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

الإجراء التجريبي

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)−.

المصدر