Recyclable catalytic synthesis of substituted quinolines: copper-catalyzed heterocyclization of 1-(2-aminoaryl)-2-yn-1-ols in ionic liquids
A convenient and simple approach for the recyclable catalytic synthesis of substituted quinolines is presented. The method is based on CuCl2-catalyzed heterocyclization of readily available 1-(2-aminoaryl)-2-yn-1-ols in BmimBF4 as the solvent at 100 °C for 15-24 h. The solvent-catalyst system could be successfully recycled up to six times without significant loss of activity.
Versatile synthesis of quinoline-3-carboxylic esters and indol-2-acetic esters by palladium-catalyzed carbonylation of 1-(2-aminoaryl)-2-Yn-1-Ols
(Chemical Equation Presented) 1-(2-Aminoaryl)-2-yn-1-ols, easily obtained by the Grignard reaction between 1-(2-aminoaryl)ketones and alkynylmagnesium bromides, were subjected to carbonylative conditions in the presence of the PdI2-KI catalytic
Novel and convenient synthesis of substituted quinolines by copper- or palladium-catalyzed cyclodehydration of 1-(2-aminoaryl)-2-yn-1-ols
(Chemical Equation Presented) A general and convenient synthesis of substituted quinolines by regioselective copper- or palladium-catalyzed 6-endo-dig cyclization-dehydration of 1-(2-aminoaryl)-2-yn-1-ols is reported. The crude substrates were easily obtained by the Grignard reaction between the appropriate alkynylmagnesium bromide and 2-aminoaryl ketones and could be used without further purification for the subsequent cyclization step. Heteroannulation reactions were carried out in MeOH or DME as the solvent at 60 or 100°C in the presence of CuCl2 or PdX2 (in conjunction with 10 equiv of KX, X = Cl, I) as the catalyst to afford the quinoline derivatives in good to excellent isolated yields based on starting 1-(2-aminoaryl)-2-yn-1-ols (66-90%).