A novel one-pot synthesis of annulated 2,2′-bipyridine ligands by inverse electron demand Diels–Alder reaction of 5,5′-bi-1,2,4-triazines
作者:Andrzej Rykowski、Danuta Branowska、Joanna Kielak
DOI:10.1016/s0040-4039(00)00436-6
日期:2000.5
The Diels–Alder reaction of 5,5′-bi-1,2,4-triazines with cyclic enamines in the absence of a solvent leads to a range of symmetrical, annulated 2,2′-bipyridines in good yield. When the reaction is carried out in boiling dioxane only 5-(heteroaryl)1,2,4-triazines are formed. The latter, bearing methylsulfanyl substituents, are oxidized with potassium permanganate to the corresponding methylsulfonyl
5,5'-联-1,2,4-三嗪与环状烯胺的狄尔斯-阿尔德反应在不存在溶剂的情况下可产生一系列对称的,环状的2,2'-联吡啶,并具有良好的收率。当反应在沸腾的二恶烷中进行时,仅形成5-(杂芳基)1,2,4-三嗪。后者带有甲基硫烷基取代基,被高锰酸钾氧化成相应的甲基磺酰基衍生物,很容易与不同的烯胺进行Diels-Alder反应,生成不对称的环状2,2'-联吡啶。