3295-64-5Relevant articles and documents
Homogeneous Catalytic Hydrogenation. 2. Selective Reduction of Polynuclear Heteroaromatic Compounds Catalyzed by Chlorotris(triphenylphosphine)rhodium(I)
Fish, Richard H.,Tan, John L.,Thormodsen, Arne D.
, p. 4500 - 4505 (1984)
The selective reduction of polynuclear heteroaromatic nitrogen compounds such as quinoline, 1, 5,6-benzoquinoline, 2, 7,8-benzoquinoline, 3, acridine, 4, phenanthridine, and in one case, a sulfur heterocyclic compound, benzothiophene, 6, with chlorotris(triphenylphosphine)rhodium(I), (Ph3P)3RhCl, provided under rather mild hydrogenation conditions the corresponding saturated nitrogen and sulfur heterocyclic analogues of the above-mentioned compounds in reasonable conversion rates and total percent yields.In addition, compounds that inhibit the initial rate of hydrogenation of 1 in the conversion to 1,2,3,4-tetrahydroquinoline, 10, include pyridine, 7, 3-methylpyridine, 8, and 10 itself.These results are indicative of electronic effects in these competitive hydrogenation reactions, while 2-methylpyridine, 9, slightly reduces the rate of hydrogenation of 1, implicating a steric effect at the metal center.It was also observed that substrate 6, indole, 11, pyrrole, 12, carbazole, 13, thiophene, 14, dibenzothiophene, 15, and p-cresol, 16, enhanced the initial rate of hydrogenation of 1 to 10 by an average factor of >1.5.The substitution of deuterium gas for hydrogen gas in the reduction of 1 provided information on the reversibility of the hydrogenation step, stereoselectivity in the reduction of the 3,4-double bond, and the implication of cyclometalation reactions which caused the exchange of H for D at the 8-position and possibly the 2-position.Similar deuteration data with compound 5 strengthened the concept of dehydrogenation in the hydrogenation step and in fact provided independent evidence for the facile dehydrogenation of 1,9,9,10-tetradeuterio-9,10-dihydrophenanthridine, 19, catalyzed by (Ph3P)3RhCl. 1H NMR and IR experiments also verify some of the postulated mechanistic aspects of these selective hydrogenation reactions.
Pincerlike manganese complex and preparation method thereof, related ligand and preparation method thereof, catalyst composition and application
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Paragraph 0144; 0145; 0147-0151, (2021/07/31)
The invention discloses a pincerlike manganese complex, a preparation method thereof, a ligand for preparation, a preparation method of the ligand, a catalyst composition taking the complex as an active component and application of the catalyst composition. According to the pincerlike manganese complex, a cycloalkyl ring is introduced into a ligand framework, and by regulating and controlling the cyclic tension, flexibility and steric hindrance of the cycloalkyl ring, the reactivity and stability of the manganese metal center can be effectively adjusted, and the catalytic activity and substrate applicability of a manganese metal system are remarkably improved. The catalyst composition taking the pincerlike manganese complex as an active component has the advantages of high catalyst activity, wide substrate application range, mild reaction conditions and the like in the process of preparing quinoline or pyridine derivatives by catalyzing dehydrogenation coupling reaction of o-amino aromatic alcohol or gamma-amino alcohol, ketone or secondary alcohol; and the synthesis advantages of low cost and stable performance are embodied, the operation is simple, and the yield is high.
Direct synthesis of ring-fused quinolines and pyridines catalyzed byNNHY-ligated manganese complexes (Y = NR2or SR)
Han, Mingyang,Lin, Qing,Liu, Qingbin,Liu, Song,Ma, Ning,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Yan, Xiuli
, p. 8026 - 8036 (2021/12/27)
Four cationic manganese(i) complexes, [(fac-NNHN)Mn(CO)3]Br (Mn-1-Mn-3) and [(fac-NNHS)Mn(CO)3]Br (Mn-4) (whereNNHis a 5,6,7,8-tetrahydro-8-quinolinamine moiety), have been synthesized and evaluated as catalysts for the direct synthesis of quinolines and pyridines by the reaction of a γ-amino alcohol with a ketone or secondary alcohol;NNHS-ligatedMn-4proved the most effective of the four catalysts. The reactions proceeded well in the presence of catalyst loadings in the range 0.5-5.0 mol% and tolerated diverse functional groups such as alkyl, cycloalkyl, alkoxy, chloride and hetero-aryl. A mechanism involving acceptorless dehydrogenation coupling (ADC) has been proposed on the basis of DFT calculations and experimental evidence. Significantly, this manganese-based catalytic protocol provides a promising green and environmentally friendly route to a wide range of synthetically important substituted monocyclic, bicyclic as well as tricyclicN-heterocycles (including 50 quinoline and 26 pyridine examples) with isolated yields of up to 93%.
[(PPh3)2NiCl2]-Catalyzed C-N bond formation reaction via borrowing hydrogen strategy: Access to diverse secondary amines and quinolines
Donthireddy,Pandey, Vipin K.,Rit, Arnab
, p. 6994 - 7001 (2021/06/09)
Commercially available [(PPh3)2NiCl2] was found to be an efficient catalyst for the mono-N-alkylation of (hetero)- A romatic amines, employing alcohols to deliver diverse secondary amines, including the drug intermediates chloropyramine (5b) and mepyramine (5c), in excellent yields (up to 97%) via the borrowing hydrogen strategy. This method shows a superior activity (TON up to 10000) with a broad substrate scope at a low catalyst loading of 1 mol % and a short reaction time. Further, this strategy is also successful in accessing various quinoline derivatives following the acceptorless dehydrogenation pathway.
