反应详情

ethyl 3-(5-mercapto-1H-1,2,4-triazol-3-yl)propanoate obtained in Reference Example 21 (650 mg, 3.23 mmol) was added slowly to a mixed solution of sodium nitrite (8.91 mg, 0.129 mmol), nitric acid (3 mL) and water (6 mL) while keeping 45° C. or less. The solution was stirred at room temperature for 15 hr, and neutralized with saturated aqueous sodium carbonate solution. The mixture was concentrated under reduced pressure, and the residue was crystallized from THF, and washed with THF. Ethanol was added thereto, and the insoluble material was filtered off. The filtrate was concentrated under reduced pressure to give the title compound as a pale-yellow powder (454 mg, 99%).

1. customwhile keeping 45° C. or less
2. concentrationThe mixture was concentrated under reduced pressure
3. customthe residue was crystallized from THF
4. washwashed with THF
5. additionEthanol was added
6. filtrationthe insoluble material was filtered off
7. concentrationThe filtrate was concentrated under reduced pressure