反应详情

In a 250 ml flask, place 10 g (0.055 m) of 3-nitrobenzamidoxime (9a), 9.6 g (0.083 m) of methyl acetoacetate (10b; R1=methyl), and 100 ml of toluene. Heat and stir the reaction mixture under reflux with a Dean-Stark trap for 16 hrs. Distill off toluene under a reduced pressure at 50-60° C. to thick oil. Add 60 ml of heptane to the oil with stirring, cool and stir at 0-5° C. for 30 min. Collect solid, wash with heptane, and dry in air to give 11.4 g (84%) of 5-(2-oxopropyl)-3-(3-nitrophenyl)-1,2,4-oxadiazole [Formula II: R1=methyl and R2=3-nitrophenyl].

1. temperatureHeat
2. temperatureunder reflux with a Dean-Stark trap for 16 hrs
3. distillationDistill off toluene under a reduced pressure at 50-60° C. to thick oil
4. additionAdd 60 ml of heptane to the oil
5. stirringwith stirring
6. temperaturecool
7. stirringstir at 0-5° C. for 30 min
8. customCollect solid
9. washwash with heptane
10. customdry in air