Phosphonylation of 2-Amino- and 2-Amido-3-bromopyridines and 2-Amino-3-chloroquinoxalines with Triethyl Phosphite
作者:M. Shaker S. Adam、Markus K. Kindermann、Martin Köckerling、Joachim W. Heinicke
DOI:10.1002/ejoc.200900698
日期:2009.9
the N atoms towards the reaction site. The advantage of the Tavs reaction is the easy optimization because neither auxiliary ligands are required nor a base to trap the halide or a solvent. Triethylphosphite itself acts as ligand and forms Pd0P(OEt)3}n in the initial phase of the reaction. The structures of the products and the expected intramolecular N–H···O=P hydrogen bridging bonds were proven
2-氨基-和2-酰氨基-3-溴吡啶1和2与亚磷酸三乙酯在乙酸钯或氯化物存在下的Tavs反应允许合成2-氨基-和2-酰氨基-3-膦酸酯3和4。第二个环氮原子引起强烈的活化,并导致 2-氨基-3-氯喹喔啉的膦酰化产生极好的收率。2,3-二氯喹喔啉不需要催化剂,在 Michaelis-Becker 条件下与二乙基亚磷酸钠发生双膦酰化反应。结果显示了吡啶氮 (-M) 的活化影响和氨基 (+M) 的失活影响。将Tavs偶联中1和2的反应性与3-NH-2-溴吡啶位置异构体和2-溴苯胺的反应性进行了比较,并从吡啶和氨基(酰氨基)氮的相反作用和不同位置的方面进行了讨论。 N 原子朝向反应位点。Tavs 反应的优点是易于优化,因为既不需要辅助配体,也不需要碱来捕获卤化物或溶剂。亚磷酸三乙酯本身作为配体并在反应的初始阶段形成 Pd0P(OEt)3}n。通过溶液核磁共振和单晶 3c 的 X 射线晶体结构分析证明了产物的结构和预期的分子内
Pyrido‐Annulated 1,3‐Azaphospholes: Synthesis of 1,3‐Azaphospholo[5,4‐
<i>b</i>
]pyridines and Preliminary Reactivity Studies
作者:Mohamed Shaker S. Adam、Peter G. Jones、Joachim W. Heinicke
DOI:10.1002/ejic.201000253
日期:2010.7
Pyrido-annulated σ 2 -phosphorus heterocycles, 1,3-azaphospholo[5,4-b]pyridines 4 and 5, were synthesized by reduction of diethyl 2-aminopyridine-3-phosphonates 1 with LiAlH 4 and cyclocondensation of the resulting 2-amino-3-phosphanylpyridines 2 with dimethylformamide and dimethylacetamide dimethyl acetal, respectively, via intermediate phosphaalkenes 3. The P=C-N heterocycles are stable in the presence