Intramolecular ring closure of the asymmetric urea derivatives so formed allows for a selectively substituted hydantoin ring to be obtained. The hydrazone side chain introduced by the conjugated heterodiene system at the 5-position of the heterocycle represents a valuable functionality for accessing novel 5-acyl derivatives difficult to obtain by other methods.
1,2-二氮杂-1,3-二烯(DDs)作为迈克尔受体与
伯胺反应,得到与
异氰酸酯原位偶联的α-
氨基hydr衍
生物。如此形成的不对称
脲衍
生物的分子内闭环使得能够获得选择性取代的乙内酰
脲环。由共轭杂二烯体系在杂环的5-位引入的side侧链代表了一种有价值的官能团,可用于获得难以通过其他方法获得的新型5-酰基衍
生物。