60807-16-1Relevant academic research and scientific papers
NHC-stabilised Rh nanoparticles: Surface study and application in the catalytic hydrogenation of aromatic substrates
Martinez-Espinar, Francisco,Blondeau, Pascal,Nolis, Pau,Chaudret, Bruno,Claver, Carmen,Castillón, Sergio,Godard, Cyril
, p. 113 - 127 (2017/09/08)
New Rh-NPs stabilised by N-Heterocyclic Carbenes (NHC) were synthesized by decomposition of [Rh(η3-C3H5)3] under H2 atmosphere and fully characterized. Surface studies by FT-IR and NMR spectroscopy employing isotopically labelled ligands were also performed. The Rh0.2 NPs are active catalysts in the reduction of various aromatic substrates. In the reduction of phenol, high selectivities to cyclohexanone or cyclohexanol were obtained depending on the reaction conditions. However, this catalytic system exhibited much lower activity in the hydrogenation of substituted phenols. Pyridine was easily hydrogenated under mild conditions and interestingly, the hydrogenation of 4-methyl and 4-trifluoromethylpyridine resulted slower than that of 2-methylpyridine. The hydrogenation of 1-(pyridin-2-yl)propan-2-one provided the β-enaminone 13a in high yield as a consequence of the partial reduction of the pyridine ring followed by isomerization. Quinoline could be either partially hydrogenated to 1,2,3,4-tetrahydroquinoline or fully reduced to decahydroquinoline by adjusting the reaction conditions.
Synthesis of [1,2-A]-fused tricyclic dihydroquinolines by palladiumcatalyzed intramolecular C-N cross-coupling of polarized heterocyclic enamines
Bro?, B?etislav,R??i?ková, Zdeňka,?im?nek, Petr
supporting information, p. 118 - 141 (2016/10/22)
A simple methodology for [1,2-A]-fused tricyclic dihydroquinolines is established. The key ste of the methodology is an intramolecular Buchwald-Hartwig amination reaction of suitabl halogenated (both bromo and chloro) cyclic enaminoketones, enaminoesters and enaminonitrile with various ring size (from five-to seven-membered). Optimal reaction conditions (palladiu source, base, ligand) depend on the ring size of the starting enamine, giving 65-98% yield of th tricyclic product. A treatment of the products with perchloric acid gives respective quinoliniu perchlorates.
A simple, enaminone-based approach to some bicyclic pyridazinium tetrafluoroborates
Josefik, Frantisek,Svobodova, Marketa,Bertolasi, Valerio,Simunek, Petr
supporting information, p. 1463 - 1471 (2013/08/23)
Easily obtainable cyclic enaminones (piperidin-2-ylidenealkanones) can be transformed into substituted bicyclic pyridazinium tetrafluoroborates upon treatment with corresponding diazonium salts. The transformation can be performed either in a one-pot way or in a two-step process with the isolation of single azo-coupled enaminone as the intermediate. The former method is superior. Under the optimized conditions, a number of pyridazinium salts substituted with both electron-donating and electron-withdrawing substituents was easily synthesized. A mechanism of the formation of the pyridazinium salts is suggested. A partial drawback is the possibility of the formation of a mixture of products when using a different diazonium salt in each step due to a reversibility of the azo coupling. This can be suppressed by using a more reactive diazonium salt before a less reactive one.
A new bicyclic oxazaborines with a bridged nitrogen atom, their thermic rearrangement and fluorescence properties
Josefík, Franti?ek,Svobodová, Markéta,Bertolasi, Valerio,?im?nek, Petr,MacHá?ek, Vladimír,Almonasy, Numan,?erno?ková, Eva
supporting information; experimental part, p. 75 - 81 (2012/02/16)
Cyclic β-enaminones bearing secondary amino group react with 4-substituted benzenediazonium tetraphenylborates in dichloromethane to form substituted bicyclic [1,3,2λ4]oxazaborines The oxazaborines rearrange, on heating to 200 °C in the absence of solvent or in DMF or DMSO, to isomeric 2H-[1,2,4,3λ4]triazaborines. Previously prepared [1,3,2λ4]oxazaborines derived from acyclic β-enaminones bearing secondary amino group either did not undergo the rearrangement or with a lot of difficulties and with negligible yield. The fluorescence behaviour of the prepared triazaborines was observed. These compounds fluoresce in 2-methyltetrahydrofurane and in solid state under low temperatures.
