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。
Experimental and theoretical studies on thermodynamics and properties of tautomers of 2-substituted 6(4)-methyl-1,4(1,6)-dihydropyrimidine-5-carboxylates
作者:Hidetsura Cho、Yoshio Nishimura、Hiroshi Ikeda、Mitsuhiro Asakura、Shinji Toyota
DOI:10.1016/j.tet.2018.03.032
日期:2018.5
Experimental and theoreticalstudies on the thermodynamics and properties of 2-substituted 6(4)-methyl-1,4(1,6)-dihydropyrimidine-5-carboxylates were undertaken by 1H NMR measurements and DFT (density functional theory) calculations. The ratios of tautomers a/b of dihydropyrimidines (DPs) 1, 2, and 3 were determined under various conditions to reveal the effects of temperature, solvent, and concentration
通过1 H NMR测量和DFT(密度泛函理论)计算,对2-取代的6(4)-甲基-1,4(1,6)-二氢嘧啶-5-羧酸酯的热力学和性质进行了实验和理论研究。互变异构体的比例一个/ b的二氢嘧啶(DPS)1,2,和3在各种条件下测定以显示温度,溶剂和浓度对热力学数据的影响。观测结果,自由能差(ΔG),焓差(ΔH)和熵差(ΔS)的分子结构,偶极矩(DM)和由DFT计算得出的静电势图以阐明DP的性质进行了讨论。