反应详情

The solution of 13 g of 1-phenyl-3-methyl-2-pyrazolin-5-one in 150 ml of benzene and 9.1 g of triethylamine is combined at ambient temperature with the solution of 14.0 g of 3,4-dichlorophenylisocyanate in the minimum amount of benzene. The triethylammonium salt separates after 2 hours standing at room temperature and the mixture is evaporated. The residue is poured into 0.3 N hydrochloric acid, the solid collected, washed with water, dried, triturated with cold methanol and recrystallized from ethyl acetate to yield the 1-phenyl-3-methyl-4-(3,4-dichlorophenylcarbamoyl)-2-pyrazolin-5-one of Formula II with R=H, R'=3--Cl and R"=Cl, melting at 228°-231° (dec.).

1. customstanding at room temperature
2. customthe mixture is evaporated
3. additionThe residue is poured into 0.3 N hydrochloric acid
4. customthe solid collected
5. washwashed with water
6. customdried
7. customtriturated with cold methanol
8. customrecrystallized from ethyl acetate