Non-noble Metal Catalyzed Synthesis And Transformation Of Quinoline

Quinoline and its derivatives are an important class of nitrogenous heterocyclic compounds with a wide range of physiological and pharmaceutical activities.Its reduction products 1,2,3,4-tetrahydroquinoline(THQ)and N-formyltetrahydroquinoline(FTHQ)are also important backbones for many bioactive compounds.At present,the preparation of quinoline is mainly based on precious metals,such as Pt,Ru,Ir,etc.Although precious metal catalysts possess superior selectivity and catalytic performance,their costly price tag impedes their widespread usage.Consequently,there is a growing research interest in developing novel catalysts or synthesis methodologies that are cost-effective and environmentally sustainable for the preparation of quinoline-derived compounds.The work in this paper is mainly divided into two parts: 1.the synthesis of quinoline and its derivatives catalyzed by cheap iron metal,2.the hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline and N-formyltetrahydroquinoline with a novel N-didentate cobalt complex.The main research contents of the paper are:Part one: Using o-aminobenzyl alcohol and acetophenone and α-phenethylalcohol as raw materials,non-noble heterogeneous iron as catalyst,non-acceptor dehydrogenation coupling combined into quinoline and its derivatives.Using acetophenone as the template substrate,the effects of different catalysts,solvents,temperatures,bases,etc.on the reaction were studied,and the target product 2-phenylquinoline,acetophenone with different substituents,heterocyclic aromatic methyl ketone and cyclic aliphatic ketone were obtained with medium to good yields with 98% yield under optimal conditions.Twenty kinds of quinolines and their derivatives were synthesized from α-phenethylalcohol with various substituents.To evaluate the feasibility of this synthetic approach,the protocol was employed in the synthesis of rutinine and targeted triple DNA.Part two: A cobalt N,N-bidentate complex was synthesized and employed as a catalyst to convert N-heteroaromatic hydrocarbons into N-formyltetrahydroquinoline(FTHQ)derivatives via reduction,with formic acid utilized as an effective and convenient transfer hydrogenation reagent that presents no significant safety concerns while also being readily available.The newly developed cobalt N,N-bidentate complexes show good ability in formic acid dehydrogenation.In addition,it has been demonstrated that THQ derivatives can be obtained by transferring hydrogenation in one pot.