Ring-chain tautomerism in 2-substituted 1,2,3,4-tetrahydroquinazolines A 1H, 13C and 15N NMR study
作者:Jari Sinkkonen、Kirill N. Zelenin、Abdul-Kadir A. Potapov、Igor V. Lagoda、Valeriy V. Alekseyev、Kalevi Pihlaja
DOI:10.1016/s0040-4020(03)00148-0
日期:2003.3
1H, 13C and 15N NMR spectroscopy. The ketone, as well as the alkyl aldehyde, derivatives were found to favor exclusively ring forms, whereas tautomeric equilibria were observed for aryl aldehyde derivatives. For para-phenyl substituted compounds, good linear correlations were found between the Hammett–Brown σ+ parameter and (K=[ring]/[chain]) and also between σ+ and δNC (NC nitrogen chemical shift)
在这项工作中,通过2-氨基甲基苯胺与醛和酮的反应合成了32 1,2,3,4-四氢喹唑啉衍生物,并通过1 H,13 C和15 N NMR光谱研究了它们的环链互变异构现象。发现酮以及烷基醛衍生物仅偏爱环形式,而对于芳基醛衍生物观察到互变异构平衡。对于对位-苯基取代的化合物,较好的线性相关性进行哈米特-布朗之间发现σ +参数和(ķ = [环] / [链]),并且还之间σ +和δ NC(NC氮化学位移)。一个良好的相关性也日志之间发现 ķ和δ NC,这表明芳基取代基的电子特性是由共轭效应的氮原子的环境中进行。