The new type of four-component tandem Knoevenagel–Michael reaction was found: assembling arylaldehydes, N,N′-dimethylbarbituric acid, 4-hydroxycoumarine, and morpholine or piperidine has been successfully carried out in alcohols, other organic solvents and water at ambient temperature without catalyst or any other additives and resulted in the selective formation of the new substituted unsymmetrical scaffold with three different heterocyclic rings in 75–98% yields. The crystal structure of morpholin-4-ium 5-[(4-hydroxy-2-oxo-2H-chromen-3-yl)(phenyl)methyl]-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate and morpholin-4-ium 5-[(4-hydroxy-2-oxo-2H-chromen-3-yl)(4-nitrophenyl)methyl]-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate was confirmed by X-ray diffraction study. Thus, this new four-component tandem Knoevenagel–Michael strategy is a selective, facile, and efficient way to unsymmetrical scaffolds with three different pharmacology active heterocyclic rings. The optimized reaction conditions and a mechanistic rationale for this multicomponent assembling are presented.

Graphic abstract

中文翻译：

---

芳醛、二甲基巴比妥酸、4-羟基香豆素和环胺的四组分直接组装成具有三个不同杂环的复杂支架

发现新型四组分串联 Knoevenagel-Michael 反应：在常温下，在醇、其他有机溶剂和水中成功组装芳醛、N , N '-二甲基巴比妥酸、4-羟基香豆素和吗啉或哌啶在没有催化剂或任何其他添加剂的情况下，选择性地形成了具有三个不同杂环的新型取代不对称支架，产率为 75-98%。morpholin-4-ium 5-[(4-hydroxy-2-oxo-2 H -chromen-3-yl)(phenyl)methyl]-1,3-dimethyl-2,6-dioxo-1的晶体结构， 2,3,6-tetrahydropyrimidin-4-olate 和morpholin-4-ium 5-[(4-hydroxy-2-oxo-2 H-chromen-3-yl)(4-nitrophenyl)methyl]-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate 通过 X 射线衍射研究证实。因此，这种新的四组分串联 Knoevenagel-Michael 策略是一种选择性、简便且有效的方法，可用于构建具有三种不同药理学活性杂环的不对称支架。介绍了这种多组分组装的优化反应条件和机械原理。

图形摘要