反应详情

A solution of benzyl N-hydroxy-N-phenylcarbamate (8.0 g) in ethanolic potassium hydroxide (0.27N; 120 ml) was treated with chloropyrazine (4.18 g) and molecular sieve (0.5 g). The mixture was stirred for 2 hours at room temperature and then allowed to stand for 4 days. Evaporation of the reaction mixture under reduced pressure gave an orange residue which was suspended in dilute acetic acid, filtered off, and heated in hot 1-propanol (about 200 ml). On cooling, the resulting solution gave a golden precipitate of 5-(4-benzyloxycarbonylaminophenyl)-2(1H)-pyrazinone m.p. 240°-244° C.

1. waitto stand for 4 days
2. customEvaporation of the reaction mixture under reduced pressure
3. customgave an orange residue which
4. filtrationfiltered off
5. temperatureheated in hot 1-propanol (about 200 ml)
6. temperatureOn cooling