反应详情

Using modifications of the method of Shine et al., J. Heterocyclic Chem. (1989) 26:125-128, a solution of picolinic acid (123 mg, 1 mmol) in pyridine (1 mL) was treated with 1,1′-carbonyldiimidazole (162 mg, 1 mmol) and the reaction stirred at ambient temperature until the evolution of carbon dioxide ceased (30 min). The intermediate acylimidazole was then treated with 3-methoxybenzamidoxime (166 mg, 1 mmol) and the reaction heated at reflux for 1 hour. Ice cold water was added to the reaction mixture to precipitate the oxadiazole. The solid was collected by filtration, washed with water and dried to afford 80 mg (32%) of 3-(3-methoxyphenyl)-5-(2-pyridyl)-1,2,4-oxadiazole: mp 90-94° C.; GC/EI-MS gave m/z (rel. int.) 253 (M+, 100), 254 (17), 179 (2), 175 (2), 149 (77), 133 (33), 119 (4), 106 (29), 78 (45), 51 (18).

1. custom(30 min)
2. temperaturethe reaction heated
3. temperatureat reflux for 1 hour
4. additionIce cold water was added to the reaction mixture
5. customto precipitate the oxadiazole
6. filtrationThe solid was collected by filtration
7. washwashed with water
8. customdried