反应详情

A reaction vessel was charged with sixty-eight grams (0.36 mole) of 3,5-dichloro-4-pyridinecarboxamide, 55.5 grams (0.36 mole) of p-chlorophenyl isocyanate, and 1200 milliliters of xylene. The solution was heated under reflux with stirring for three hours. A small amount of impurity was removed by filtering the hot reaction mixture. On cooling in an ice water bath, a solid precipitated. The precipitated product was collected by suction filtration, washed with cold xylene and dried in a vacuum oven at about 70° C. The dried crude product was purified by recrystallization from 90 percent aqueous acetic acid. The yield was 81 grams (66 percent of theoretical) of white needles melting at 225°-227° C. Nuclear magnetic resonance spectral data confirmed the structure as being ##STR12##

1. temperatureThe solution was heated
2. temperatureunder reflux
3. customA small amount of impurity was removed
4. filtrationby filtering the hot reaction mixture
5. temperatureOn cooling in an ice water bath
6. customa solid precipitated
7. filtrationThe precipitated product was collected by suction filtration
8. washwashed with cold xylene
9. customdried in a vacuum oven at about 70° C
10. customThe dried crude product
11. customwas purified by recrystallization from 90 percent aqueous acetic acid