54810-34-3

Upstream product

• 6640-50-2 1,2,3,4-tetrahydroquinolin-8-ol 
• 130-16-5 5-Chloro-8-hydroxyquinoline 

Relevant academic research and scientific papers

Boron-Catalyzed Hydrogenative Reduction of Substituted Quinolines to Tetrahydroquinolines with Hydrosilanes

A metal-free procedure for the hydrogenative reduction of substituted N-heteroaromatics has been developed by using hydrosilanes as reducing agents. The optimized conditions were successfully applied to the reactions of quinolines, quinoxalines, and quinoline N -oxides. They were also effective for the reduction of quinolines bearing amino or hydroxy groups, where H 2 was evolved through dehydrogenative silylation of the amine or hydroxy moieties. Preliminary mechanistic studies revealed that the initial step in the catalytic cycle involves 1,4-addition of the hydrosilane to the quinoline to give a 1,4-dihydroquinoline; this is followed by (transfer) hydrogenation to deliver the tetrahydroquinoline as the final product.

Method for preparing 1,2,3,4-tetrahydroquinoline compound

The invention discloses a method for preparing a 1,2,3,4-tetrahydroquinoline compound. The reaction formula of the synthesis method is shown in the description. In the reaction formula, R represents aromatic ring groups; a catalyst is prepared from polymer microsphere loaded metal nanoparticles; the general formula of the catalyst is Poly(X-co-Y)M. The method is characterized by reacting under the normal temperature and normal pressure; an efficient, simple and safe method is supplied to preparation of the 1,2,3,4-tetrahydroquinoline compound.

Selective N-cycle hydrogenation of quinolines with sodium borohydride in aqueous media catalyzed by hectorite-supported ruthenium nanoparticles: Dedicated to Professor Heinrich Lang on the occasion of his 60th birthday

A new catalyst containing metallic ruthenium nanoparticles intercalated in hectorite (nanoRu'@hectorite) was found to catalyze the reduction of quinoline and quinoline derivatives by NaBH4in aqueous solution to give selectively the corresponding 1,2,3,4-tetrahydroquinolines (N-cycle hydrogenation). In most cases the reaction can be done under mild conditions (25–60 °C) without pressure equipment, conversion and selectivity being superior to 99%. In the case of sterically hindered derivatives, the reaction can be done in a pressure vessel under self-generated pressure (up to 9 bar). Isoquinoline and quinoxalines also undergo selective N-cycle hydrogenation, but 2-phenyl-quinoline is hydrogenated to give 2-phenyl-5,6,7,8-tetrahydroquinoline (C-cycle hydrogenation). Isotope labeling experiments combined with semi-empirical calculations of the electrostatic potentials support a heterolytic hydrogenation mechanism involving a hydride from NaBH4and a proton from H2O. The catalyst nanoRu'@hectorite can be recycled and reused.

An unusual chemoselective hydrogenation of quinoline compounds using supported gold catalysts

The pursuit of modern sustainable chemistry has stimulated the development of innovative catalytic processes that enable chemical transformations to be performed under mild and clean conditions with high efficiency. Herein, we report that gold nanoparticles supported on TiO2 catalyze the chemoselective hydrogenation of functionalized quinolines with H2 under mild reaction conditions. Our results point toward an unexpected role for quinolines in gold-mediated hydrogenation reactions, namely that of promoter; this is in stark contrast to what prevails in the traditional noble metal Pd-, Pt-, and Ru-based catalyst systems, in which quinolines and their derivatives typically act as poisons. As a result of the remarkable promotional effect of quinoline molecules to H2 activation over supported gold, the transformation can proceed smoothly under very mild conditions (even at temperatures as low as 25 °C). Of practical significance is that various synthetically useful functional groups including halogens, ketone, and olefin remain intact during the hydrogenation of quinolines. Moreover, the protocol also shows promise for the regiospecific hydrogenation of the heterocyclic ring of a variety of other biologically important heteroaromatic nitrogen compounds, such as isoquinoline, acridine, and 7,8-benzoquinoline, in a facile manner. Apart from its importance in catalytic hydrogenation, we believe that this intriguing self-promoted effect by reactant molecules may have fundamental implications for the broad field of gold catalysis and form the basis for development of new catalytic procedures for other key transformations.

Substituted benzoxazine derivatives and fungicidal use

Novel Substituted benzoxazine derivatives of the formula STR1 in which X is oxygen or suophur, and R1 and R2 each independently is hydrogen, alkyl, alkoxy, akylthio, halogenoalkyl, alkanoyl, aroyl, halogen, cyano, nitro, nitroso, amino or the suophonic acid grouping, with the restriction that either of R1 and R2 does not represent hydrogen if the other represents hydrogen, the 6-methyl group, the 6-ethyl group, the 6-butyl group or the 6-acetyl group and X is oxygen, which possess fungicidal activity. A few related compounds, though known, also possess such activity.