- Chemoselective Hydrogenation of Nitroarenes Catalyzed by Molybdenum Sulphide Clusters
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Herein, we describe an atom efficient and general protocol for the chemoselective hydrogenation of nitroarenes to anilines catalyzed by well-defined diimino and diamino cubane-type Mo3S4 clusters. The novel diimino [Mo3S4Cl3(dnbpy)3]+ ([5]+) (dnbpy=4,4′-dinonyl-2,2′-dipyridyl, L1) trinuclear complex was synthesized in high yields by simple ligand substitution reactions starting from the thiourea (tu) [Mo3S4(tu)8(H2O)]Cl4?4 H2O (3) precursor. This strategy has also been successfully adapted for the isolation of the diamino [Mo3S4Cl3(dmen)3](BF4) ([6](BF4)), (dmen=N,N′-dimethylethylenediamine) salt. Applying these catalysts, high selectivity in the hydrogenation of functionalized nitroarenes has been accomplished. Over thirty anilines bearing synthetically functional groups have been synthesized in 70 to 99 % yield. Notably, the integrity of the cluster core is preserved during catalysis. Based on kinetic studies on the hydrogenation of nitrobenzene and other potential reaction intermediates, the direct reduction to aniline is the preferential route.
- Pedrajas, Elena,Sorribes, Iván,Gushchin, Artem L.,Laricheva, Yuliya A.,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
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p. 1128 - 1134
(2017/03/27)
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- Nanoscale Fe2O3-based catalysts for selective hydrogenation of nitroarenes to anilines
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Production of anilines - key intermediates for the fine chemical, agrochemical, and pharmaceutical industries - relies on precious metal catalysts that selectively hydrogenate aryl nitro groups in the presence of other easily reducible functionalities. Herein, we report convenient and stable iron oxide (Fe2O3) - based catalysts as a more earth-abundant alternative for this transformation. Pyrolysis of iron-phenanthroline complexes on carbon furnishes a unique structure in which the active Fe2O 3 particles are surrounded by a nitrogen-doped carbon layer. Highly selective hydrogenation of numerous structurally diverse nitroarenes (more than 80 examples) proceeded in good to excellent yield under industrially viable conditions.
- Jagadeesh, Rajenahally V.,Surkus, Annette-Enrica,Junge, Henrik,Pohl, Marga-Martina,Radnik, Joerg,Rabeah, Jabor,Huan, Heming,Schunemann, Volker,Brueckner, Angelika,Beller, Matthias
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p. 1073 - 1076
(2014/01/06)
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- The development of benzimidazoles as selective rho kinase inhibitors
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Rho Kinase (ROCK) is a serine/threonine kinase whose inhibition could prove beneficial in numerous therapeutic areas. We have developed a promising class of ATP-competitive inhibitors based upon a benzimidazole scaffold, which show excellent potency toward ROCK (IC50 10 nM). This report details the optimization of selectivity for ROCK over other related kinases such as Protein kinase A (PKA).
- Sessions, E. Hampton,Smolinski, Michael,Wang, Bo,Frackowiak, Bozena,Chowdhury, Sarwat,Yin, Yan,Chen, Yen Ting,Ruiz, Claudia,Lin, Li,Pocas, Jennifer,Schr?ter, Thomas,Cameron, Michael D.,LoGrasso, Philip,Feng, Yangbo,Bannister, Thomas D.
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scheme or table
p. 1939 - 1943
(2010/09/03)
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- Synthesis of Mutagenic Methyl- and Phenyl-substituted 2-Amino-3H-imidazoquinoxalines via 2,1,3-Benzoselenadiazoles
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2-Amino-3-methyl-3H-imidazoquinoxaline, all its derivatives with 1-4 methyl groups in positions 4, 5, 7 and 8, and 2-amino-3,5-dimethyl-7,8-diphenyl-3H-imidazoquinoxaline have been synthesized from the corresponding 6-methylamino-5-nitroquinoxalines through reduction and cyclization with cyanogen bromide.The quinoxalines were obtained from the appropriate α-dicarbonyl compounds and 4-methylamino-3-nitro-1,2-benzenediamines.The latter were prepared from 4-halo-1,2-benzenediamines via 2,1,3-benzoselenadiazoles.The 7- and 8-phenyl derivatives of 2-amino-3,5-dimethyl-3H-imidazoquinoxaline have been synthesized in a slightly different way.
- Grivas, Spiros,Tian, Wei,Ronne, Erik,Lindstroem, Stefan,Olsson, Kjell
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p. 521 - 528
(2007/10/02)
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