反应详情

温度

50 °C

Zinc powder (40.00 g; 0.61 mole) is added to a stirred suspension of 48.00 g (0.16 mole) of the benzylidine hydantoin from Example 3 in 1,200 mL of methanol under nitrogen. Concentrated hydrochloric acid (30 mL) is added and the mixture is heated on the steam bath for 20 minutes (after 10 minutes the starting benzylidene hydantoin dissolves). Another 30 mL of concentrated hydrochloric acid is added and the mixture is heated at reflux for another 20 minutes. The cooled (50° C.) mixture is cautiously filtered and the cake washed with 100 mL of methanol. Water (500 mL) is added to the filtrate to yield 24.60 g of crystalline product; mp 202°-204° C. Recrystallization from methanol gives pure product; mp 205°-207° C.

1. dissolutiondissolves)
2. temperaturethe mixture is heated
3. temperatureat reflux for another 20 minutes
4. filtrationis cautiously filtered
5. washthe cake washed with 100 mL of methanol
6. additionWater (500 mL) is added to the filtrate