Castro-Tamay Pablo, Villaman David, Hamon Jean-René, Novoa Néstor
Laboratorio de Química Inorgánica y Organometálica, Departamento de Química Analítica e Inorgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Casilla 160-C, Concepción 4070386, Chile.
Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000 Rennes, France.
Molecules. 2024 Dec 12;29(24):5863. doi: 10.3390/molecules29245863.
Organic compounds with 1,3-diketone or 3-amino enone functional groups are extremely important as they can be converted into a plethora of carbo- or heterocyclic derivatives or can be used as ligands in the formation of metal complexes. Here, we have achieved the preparation of a series of non-symmetrical β-ketoenamines (O,N,N proligand) of the type (4-MeOCH)C(=O)CH=C(R)NH(Q) obtained through the Schiff base condensation of 1,3-diketones (1-anisoylacetone, 1-anisyl-3-(4-cyanophenyl)-1,3-propanedione, and 1-anisyl-3-(4,4,4-trifluorotolyl)-1,3-propanedione) functionalized with electron donor and electron-withdrawing substituents and 8-aminoquinoline (R = CH, 4-CHCN, 4-CHCF; Q = CHN). Schiff base ketoimines with a pendant quinolyl moiety were isolated as single regioisomers in yields of 22-56% and characterized with FT-IR, H NMR, and UV-visible spectroscopy, as well as single-crystal X-ray crystallography, which allowed for the elucidation of the nature of the isolated regioisomers. The regioselectivity of the condensation of electronically unsymmetrical 1,3-diaryl-1,3-diketones with 8-aminoquinoline was studied by H NMR, providing regioisomer ratios of ~3:1 and ~2:1 in the case of CN and CF substituents, respectively. The electronic effects correlate well with the difference between the Hammett coefficients of the two substituents on the aryl rings.
具有1,3 - 二酮或3 - 氨基烯酮官能团的有机化合物极其重要，因为它们可以转化为大量的碳环或杂环衍生物，或者在金属配合物的形成中用作配体。在此，我们通过1,3 - 二酮（1 - 茴香酰丙酮、1 - 茴香基 - 3 -（4 - 氰基苯基）- 1,3 - 丙二酮和1 - 茴香基 - 3 -（4,4,4 - 三氟甲苯基）- 1,3 - 丙二酮）与8 - 氨基喹啉（R = CH、4 - CHCN、4 - CHCF；Q = CHN）的席夫碱缩合反应，成功制备了一系列通式为(4 - MeOCH)C(=O)CH = C(R)NH(Q)的非对称β - 酮烯胺（O,N,N前配体）。带有喹啉基侧链的席夫碱酮亚胺以单一区域异构体形式分离得到，产率为22% - 56%，并通过傅里叶变换红外光谱、核磁共振氢谱、紫外 - 可见光谱以及单晶X射线晶体学进行了表征，这使得能够阐明分离得到的区域异构体的性质。通过核磁共振氢谱研究了电子不对称的1,3 - 二芳基 - 1,3 - 二酮与8 - 氨基喹啉缩合反应的区域选择性，在氰基和三氟甲基取代基的情况下，区域异构体比例分别约为3:1和2:1。电子效应与芳环上两个取代基的哈米特系数之差具有良好的相关性。
