1658-08-8Relevant articles and documents
SYNTHESIS OF ANNELATED PYRIDINES FROM 1,5-DIKETONE EQUIVALENTS USING CUPRIC ACETATE AND AMMONIUM ACETATE
Bell, Thomas W.,Rothenberger, Scott D.
, p. 4817 - 4820 (1987)
Cupric acetate serves as a mild oxidant in the efficient synthesis of 1,2,3,4,5,6,7,8-octahydroacridines 2 and 7 from a 1,5-diketone (6) a ketoalcohol (1) or a 4H-pyran (5) using ammonium acetate in acetic acid.
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Vysotskii,Tilichenko
, (1969)
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Dorofeenko et al.
, p. 1821,1824 (1966)
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Hydrogenation of N-Heteroarenes Using Rhodium Precatalysts: Reductive Elimination Leads to Formation of Multimetallic Clusters
Kim, Sangmin,Loose, Florian,Bezdek, Máté J.,Wang, Xiaoping,Chirik, Paul J.
, p. 17900 - 17908 (2019/11/19)
A rhodium-catalyzed method for the hydrogenation of N-heteroarenes is described. A diverse array of unsubstituted N-heteroarenes including pyridine, pyrrole, and pyrazine, traditionally challenging substrates for hydrogenation, were successfully hydrogenated using the organometallic precatalysts, [(η5-C5Me5)Rh(N-C)H] (N-C = 2-phenylpyridinyl (ppy) or benzo[h]quinolinyl (bq)). In addition, the hydrogenation of polyaromatic N-heteroarenes exhibited uncommon chemoselectivity. Studies into catalyst activation revealed that photochemical or thermal activation of [(η5-C5Me5)Rh(bq)H] induced C(sp2)-H reductive elimination and generated the bimetallic complex, [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H]. In the presence of H2, both of the [(η5-C5Me5)Rh(N-C)H] precursors and [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H] converted to a pentametallic rhodium hydride cluster, [(η5-C5Me5)4Rh5H7], the structure of which was established by NMR spectroscopy, X-ray diffraction, and neutron diffraction. Kinetic studies on pyridine hydrogenation were conducted with each of the isolated rhodium complexes to identify catalytically relevant species. The data are most consistent with hydrogenation catalysis prompted by an unobserved multimetallic cluster with formation of [(η5-C5Me5)4Rh5H7] serving as a deactivation pathway.
Vapor phase synthesis of annelated pyridines over metal modified zeolite beta
Macharla, Arun Kumar,Marri, Mahender Reddy,Peraka, Swamy,Mameda, Naresh,Kodumuri, Srujana,Kandepi, V. V. Krishna Mohan,Nama, Narender
, p. 1922 - 1930 (2019/11/28)
Vapor phase synthesis of annelated pyridines from cyclic ketones, aldehydes and ammonia was carried out over various zeolite molecular sieves like Hβ, HZSM-5 (240), HZSM-5 (40), HY, HX, HMCM-41 and Mordenite. The preliminary screening of catalyst clearly shows that Hβ catalyst was found to be more active for the vapor phase synthesis of annelated pyridines. Hβ was further modified with transition metals like Fe, Cu, Pb, Mo, Zn, Ni, Co, Ce, W and Sn to get higher yields.