Synthesis of 4-unsubstituted dihydropyrimidines. Nucleophilic substitution at position-2 of dihydropyrimidines
作者:Hidetsura Cho、Yoshio Nishimura、Yoshizumi Yasui、Satoshi Kobayashi、Shin-ichiro Yoshida、Eunsang Kwon、Masahiko Yamaguchi
DOI:10.1016/j.tet.2011.01.092
日期:2011.4
Synthesis of novel 4-unsubstituted dihydropyrimidines (DPs) was performed. Subsequently, a variety of 4-unsubstituted 1,4(3,4)-DPs with amino moieties at position-2 were obtained in excellent yields by activation of position-2 owing to regioselective alkoxycarbonylation at position-3 of the DP skeleton. 3-Oxo-2-phenyl-2,3,5,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrimidine was obtained using phenylhydrazine
进行了新型的4-未取代的二氢嘧啶(DPs)的合成。随后,由于在DP骨架的位置3处的区域选择性烷氧羰基化,通过位置2的活化,以优异的产率获得了在位置2具有氨基部分的各种4-未取代的1,4(3,4)-DP。使用苯肼代替胺获得3-氧代-2-苯基-2,3,5,8-四氢[1,2,4]三唑并[4,3- a ]嘧啶。根据温度和浓度,在一种衍生物的1 H NMR光谱中观察到1,4(3,4)-DP的各个互变异构体。另一方面,通过单晶X射线晶体学仅发现了固态的1,4-DP。