Hexafluoroisopropanol as solvent and promotor in the Paal-Knorr synthesis of N-substituted diaryl pyrroles
作者:Robert H.E. Schirmacher、Daniel Rösch、Franziska Thomas
DOI:10.1016/j.tet.2021.131985
日期:2021.3
An additive-free synthesis of challenging N-substituted aryl pyrroles from the often poorly soluble corresponding 1,4-diketones by means of the Paal-Knorr pyrrole synthesis is reported, which makes use of the unique properties of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a solvent and reaction promotor. Our procedure offers simple execution and purification as well as easy scale-up and can be applied
据报道,通过Paal-Knorr吡咯合成方法,由通常难溶的相应1,4-二酮可无添加剂合成具有挑战性的N-取代的芳基吡咯,该方法利用了1,1,1,3的独特性质,3,3-六氟异丙醇(HFIP)作为溶剂和反应促进剂。我们的程序提供了简单的执行和纯化方法,以及易于放大的规模,可用于Paal-Knorr合成中,结构复杂的许多吡咯,包括中等难度到极高产率的具有挑战性的四和五取代的吡咯。HFIP也可以用作呋喃和噻吩的Paal-Knorr合成中的溶剂。然而,在吡咯的合成中,溶剂作用更为明显。