Lithiation of N,N,N′,N′-tetraisopropylpyridine-2,6-dicarboxamide: synthesis, characterization and single crystal X-ray studies of chalcogen (Se/Te) derivatives of N,N,N′,N′-tetraisopropylpyridine-2,6-dicarboxamide
作者:Jaspreet S. Dhau、Rupy Dhir、Avtar Singh、Amritpal Singh、Paula Brandão、Vítor Félix
DOI:10.1016/j.tet.2014.05.066
日期:2014.8
isolated products corresponded to the double lithiation of 1 and the other to the ortho lithiation followed by nucleophilic addition of n-BuLi to the one of the two carbonyl moieties. The prepared compounds have been characterized by single crystal X-ray crystallography, NMR (1H, 13C, 77Se and 125Te), IR, UV–Visible and Mass spectroscopy. Crystal structure of N,N,N′,N′-tetraisopropyl-3,5-bis(methyltelluryl)pyridine-2
研究了N,N,N ',N'-四异丙基吡啶-2,6-二甲酰胺(1)的锂化及其在硫属元素(Se / Te)衍生物的合成中的应用。发现反应的选择性随所用的n -BuLi量的变化而变化。1与6.1当量的n- BuLi锂化,随后与硒/碲和碘甲烷反应,以优异的收率独家提供了单取代的硫族元素衍生物(2a / 2b)。但是,使用2.1或4.2当量的n -BuLi会产生两种附加产物2a / 2b。一个分离的产品的对应于的双锂化1和对方的邻位锂化,然后通过亲核加成的Ñ正丁基锂的两个羰基部分中的所述一个。制备的化合物已通过单晶X射线晶体学,NMR(1 H,13 C,77 Se和125 Te),IR,紫外可见光谱和质谱进行了表征。N,N,N ',N'-四异丙基-3,5-双(甲基碲烷基)吡啶-2,6-二甲酰胺(3b)的晶体结构显示出很强的分子内CO⋯Te二级和分子间Te⋯π吡啶基相互作用。