3-Amino-5-phenylthiophene-2-carboxamide → 6-Phenyl-3H-thiopheno[3,2-d]1,2,3-triazin-4-one

Temperature

0 °C

To an ice cold solution (0° C.) of 3-amino-5-phenylthiophene-2-carboxamide (0.37 g, 1.7 mmol) in concentrated sulfuric acid (20 mL) was added a cold (0° C.) solution of sodium nitrite (120 mg, 1.86 mmol) in concentrated sulfuric acid (8 mL) for 10 min (while adding, the temperature should keep between −5-0° C.). After addition, the mixture was stirred at 0° C. for 1 h and at rt for 1 h. The reaction mixture was cooled and 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 (3×50 mL) and the combined EtOAc layer was washed with water, brine and dried over sodium sulfate. The solution was filtered and evaporated the solvent to give the product as an off-white color solid (200 mg, 39%), my 178-180° C. 1H NMR (400 MHz, CDCl3): δ 12.30 (1H, br s), 7.86 (1H, s), 7.73-7.75 (2H, m), 7.49-7.54 (3H, m); LC-MS (negative ion mode): m/z 228 (M−H)−.

1. additionwhile adding
2. customshould keep between −5-0° C.
3. additionAfter addition
4. temperatureThe reaction mixture was cooled
5. additionpoured
6. custominto crushed ice slowly
7. stirringwith stirring for 15 min
8. stirringstirred at the same temperature for 15 min
9. extractionThe solution was extracted with ethyl acetate (3×50 mL)
10. washthe combined EtOAc layer was washed with water, brine
11. dry with materialdried over sodium sulfate
12. filtrationThe solution was filtered
13. customevaporated the solvent

ORD record

ord-8458212f8a654fc690f4add027b83ee3

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08258119B2