Tautomeric equilibria in the reaction products of asymmetric 1,3-diamines with β-dicarbonyl compounds
作者:Olga A. Maloshitskaya、Valery V. Alekseyev、Jari Sinkkonen、Kirill N. Zelenin、Kalevi Pihlaja
DOI:10.1016/j.tet.2006.07.033
日期:2006.10
Abstract The reaction products of 1,3-butanediamine and 2-methyl-2,4-pentanediamine with β-keto aldehydes were shown by 1H and 13C NMR spectroscopy to exist as tautomeric mixtures in solutions, comprising one cyclic and two open-chain forms due to the non-equivalence of the amino groups. The chain products exist as Z- and E-isomers. After equilibration, the products from 1,3-butanediamine contain relatively
摘要 1,3-丁二胺和 2-甲基-2,4-戊二胺与 β-酮醛的反应产物通过 1H 和 13C NMR 光谱显示在溶液中以互变异构体混合物的形式存在,包括一种环状和两种开链形式由于氨基的不等价性。链产物以 Z 和 E 异构体形式存在。平衡后,1,3-丁二胺的产物比 2-甲基-2,4-戊二胺的产物含有相对较少的环状形式。2-甲基-2,4-戊二胺与对位取代的芳酰乙醛的产物,在环链平衡的 log K 和芳环取代基的 Hammett σ 值之间表现出线性相关性。β-酮醛的α-取代显着增加了它们缩合产物中链式E-异构体的相对量,并且还导致每个环状产物形成两种非对映异构体。在 1,3-丁二胺和 2-甲基-2,4-戊二胺与 β-二酮、β-酮酯或 β-酮酰胺的产物中未观察到环链平衡。