反应详情

A solution of 16.20 g (0.05 mole) of the benzylidene hydantoin from Example 4 in 100 mL of methanol and 25.0 g (0. 055 mole) of 20% tetramethylammonium hydroxide-in-methanol is reduced with hydrogen and Raney nickel catalyst. After the theoretical uptake of hydrogen the mixture is filtered and acetic acid (ca 5 mL) and then water is added until just turbid. The first crop of solid is filtered. This is starting material. An additional 2 L of water is added to precipitate the product as crop 2; wt 7.60 g (47% yield). Recrystallization from methanol gives pure product; mp 155°-157° C. Anal. Calc. for C18H18N2O4 : C, 66.24; H, 5.56; N, 8.59. Found: C, 66.19; H, 5.60; N, 8.68.

1. filtrationAfter the theoretical uptake of hydrogen the mixture is filtered
2. additionacetic acid (ca 5 mL) and then water is added until just turbid
3. filtrationThe first crop of solid is filtered
4. additionAn additional 2 L of water is added
5. customto precipitate the product as crop 2
6. customRecrystallization from methanol
7. customgives pure product