以四氯化锆为催化剂, 靛红、1,3-二甲基巴比妥酸/1,3-茚二酮在脂肪醇中能够通过多组分串联反应, 有效地转化成为相应的稠环化合物嘧啶并[4,5-b]喹啉-2,4(1H,3H)-二酮和11H-茚[1,2-b]喹啉-11-酮, 并巧妙地在这些含氮杂环中引入酯基. 这些未见文献报道的化合物均通过了¹H NMR、¹³C NMR、IR和HRMS进行了表征, X射线单晶衍射确定了11H-茚并[1,2-b]喹啉-11-酮-10-羧酸乙酯(4q)的结构. 这种以简单易得化合物为原料在温和条件下制备上述两类稠环骨架的方法, 是对这些稠环骨架已有合成方法的补充, 可以有效丰富此类杂环化合物库.

Using zirconium tetrachloride as the catalyst, a multicomponent tandem reaction of isatin, 1,3-dimethyl barbituric acid/1,3-indanedione and aliphatic alcohol, effectively gave the corresponding fused-ring compounds pyrimido[4,5-b]quino- lone-2,4-(1H,3H)-diones and 11H-indeno[1,2-b]quinolin-11-ones. The ester group was introduced into these nitrogen-containing molecules. All these newly synthesized compounds were identified by means of ¹H NMR, ¹³C NMR, IR and HRMS. Moreover, ethyl-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimido[4,5-b]quinoline-5-carboxylate (4q) was confirmed by X-ray single crystal diffraction analysis. Owing to the mild reaction conditions and simple easy available starting materials, the method for the preparation of the above two fused-ring skeletons is complementary to the existing methods, which can effectively enrich the corresponding heterocyclic compound library.