反应详情

温度

0 °C

NaNO2 (0.20 g, 2.76 mmol) was added in portions to concentrated H2SO4 (1.4 mL) at 0° C. The mixture was heated at 50° C. until all of the NaNO2 had dissolved and the mixture was again cooled to 0° C. A solution of 5-[4-(methylsulfonyl)phenyl]-2-pyrazinamine (0.51 g, 2.05 mmol) in concentrated H2SO4 (4.2 mL) was added dropwise to the nitronium solution. The ice bath was removed, and the mixture was warmed to ambient temperature and stirred for 15 min, then heated to 45° C. for 30 min. The mixture was cooled to ambient temperature and poured into ice water. The pH was adjusted to about 4 with 4N NaOH and the solid was collected, washed with water, and air dried to give 0.415 g (81%) of 5-[4-(methylsulfonyl)phenyl]-2-pyrazinol (and tautomers thereof) as a brown solid. 1H NMR (400 MHz, DMSO-d6): δ 12.77 (bs, 1H), 8.30-8.05 (m, 4H), 7.92 (d, 2H, J=8.6 Hz), 3.21 (s, 3H); LRMS (ESI), m/z 251 (M+H).

1. dissolutionhad dissolved
2. customThe ice bath was removed
3. temperaturethe mixture was warmed to ambient temperature
4. temperatureheated to 45° C. for 30 min
5. temperatureThe mixture was cooled to ambient temperature
6. additionpoured into ice water
7. customthe solid was collected
8. washwashed with water, and air
9. customdried