1531-62-0

Upstream product

• 110-43-0 n-pentyl methyl ketone 
• 253-83-8 1,2,3-benzotriazine 
• 219584-93-7 [1-Ethyl-pent-(Z)-ylidene]-phenyl-amine 
• 187964-68-7 N-(1H-1,2,3-benzotriazol-1-ylmethylene)-N-methylmethanaminium chloride 
• 5344-90-1 2-Aminobenzyl alcohol 
• 106-35-4 heptan-3-one 
• 33334-08-6 1H-indazol-1-amine 

Relevant academic research and scientific papers

Improved ruthenium catalysts for the modified Friedlaender quinoline synthesis

Herein we describe an improved ruthenium catalyst for the oxidative cyclization of 2-aminobenzylalcohol with ketones, leading to quinolines via a modified Friedlaender synthesis. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Base-mediated synthesis of quinolines: an unexpected cyclization reaction between 2-aminobenzylalcohol and ketones

Quinolines are prepared in an oxidative cyclization reaction between 2-aminobenzylalcohol and ketones. This reaction, that involves a hydrogen transfer, is mediated solely by a base without the need for a transition metal catalyst.

Highly enantioselective hydrogenation of quinolines using phosphine-free chiral cationic Ruthenium catalysts: Scope, mechanism, and origin of enantioselectivity

Asymmetric hydrogenation of quinolines catalyzed by chiral cationic η6-arene-N-tosylethylenediamine-Ru(II) complexes have been investigated. A wide range of quinoline derivatives, including 2-alkylquinolines, 2-arylquinolines, and 2-functionalized and 2,3-disubstituted quinoline derivatives, were efficiently hydrogenated to give 1,2,3,4-tetrahydroquinolines with up to >99% ee and full conversions. This catalytic protocol is applicable to the gram-scale synthesis of some biologically active tetrahydroquinolines, such as (-)-angustureine, and 6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline, a key intermediate for the preparation of the antibacterial agent (S)-flumequine. The catalytic pathway of this reaction has been investigated in detail using a combination of stoichiometric reaction, intermediate characterization, and isotope labeling patterns. The evidence obtained from these experiments revealed that quinoline is reduced via an ionic and cascade reaction pathway, including 1,4-hydride addition, isomerization, and 1,2-hydride addition, and hydrogen addition undergoes a stepwise H+/H- transfer process outside the coordination sphere rather than a concerted mechanism. In addition, DFT calculations indicate that the enantioselectivity originates from the CH/π attraction between the η6-arene ligand in the Ru-complex and the fused phenyl ring of dihydroquinoline via a 10-membered ring transition state with the participation of TfO- anion.

A ruthenium-catalyzed approach to the friedlaender quinoline synthesis

In a modification of the Friedlaender reaction, 2-aminobenzyl alcohol is oxidatively cyclized with a variety of ketones to yield substituted quinolines. Of all the ruthenium catalysts that were tested for this reaction, the second-generation Grubbs' catalyst gives the highest quinoline yield, in combination with KOtBu as a base. The presence of a hydrogen acceptor is required to regenerate the catalyst. Also the reaction mechanism is discussed, and the results show that there are possibly two different pathways towards quinolines. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Diels-Alder reaction of 1,2,3-benzotriazine with enamine: Application to the synthesis of alkaloids, 2-propylquinoline and 2-pentylquinoline

The Diels-Alder reaction of 1,2,3-benzotriazine with several pyrrolidine enamines of carbonyl compounds was carried out in chloroform in the presence of zinc bromide to afford 2- or 3-mono-, or 2,3-disubstituted quinolines. This method was applied to the synthesis of the alkaloids, 2-propylquinoline and 2-pentylquinoline.