- Mechanistic Studies on the Palladium-Catalyzed Direct C-5 Arylation of Imidazoles: The Fundamental Role of the Azole as a Ligand for Palladium
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An in-depth mechanistic study on the palladium-catalyzed direct arylation of imidazoles at the C-5 position is presented. The interactions of triphenylphosphine (PPh3)-ligated aryl-Pd species with 1,2-dimethyl-1H-imidazole (dmim) have been studied in detail. In contrast with previous suggestions, phosphine-ligated organo-Pd species are not active and the reaction proceeds through imidazole-ligated organo-Pd intermediates. The kinetics of the oxidative addition of aryl halides with dmim-ligated Pd(0) species have been characterized in a Pd(dba)2/dmim model system. A thorough study of the equilibria involving novel [ArPd(dmim)2X] complexes (X=I, OAc) and the unexpected cationic [ArPd(dmim)3]+ is also reported. The ability of these species to effect the C-H arylation of dmim at room temperature in the presence of acetate is also demonstrated.
- Perego, Luca Alessandro,Grimaud, Laurence,Bellina, Fabio
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p. 597 - 609
(2016/02/27)
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- Highly regioselective C-5 alkynylation of imidazoles by one-pot sequential bromination and Sonogashira cross coupling
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A variety of 2-substituted 5-alkynyl-1H-imidazoles were easily prepared by a one-pot sequential procedure involving a highly regioselective electrophilic C-5 bromination of 1,2-dimethyl-1H-imidazole, 2-chloro-1-methyl-1H-imidazole, and 2-aryl-1-methyl-1H-imidazoles, followed by an efficient palladium/copper co-catalyzed Sonogashira-type alkynylation.
- Bellina, Fabio,Lessi, Marco,Marianetti, Giulia,Panattoni, Alessandro
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supporting information
p. 3855 - 3857
(2015/06/08)
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- HETEROARYL LINKED QUINOLINYL MODULATORS OF RORyt
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The present invention comprises compounds of Formula I. wherein: R1, R2, R3, R4, R5, R6, R7, R8, and R9 are defined in the specification. The invention also comprises a method of treating or ameliorating a syndrome, disorder or disease, wherein said syndrome, disorder or disease is rheumatoid arthritis or psoriasis. The invention also comprises a method of modulating RORγt activity in a mammal by administration of a therapeutically effective amount of at least one compound of claim 1.
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Paragraph 0332
(2014/05/07)
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- Development of an efficient process towards the benzimidazole BYK308944: A key intermediate in the synthesis of a potassium-competitive acid blocker
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An entirely new synthesis of the important benzimidazole building block BYK308944 was elaborated using the Stobbe reaction as central element. BYK308944 constitutes an important intermediate for the preparation of 3,6,7,8-tetrahydrochromeno[7,8-d] imidazoles as potassium-competitive acid blockers. The new route relies on the hydroxymethylation of 1,2- dimethylimidazole as cheap starting material followed by oxidation of the corresponding alcohol and Stobbe condensation of the resulting aldehyde with diethyl succinate. All synthetic steps of this new approach were optimized particularly with the goal to establish a process amenable for large- scale preparation.
- Webel, Matthias,Palmer, Andreas Marc,Scheufler, Christian,Haag, Dieter,Mueller, Bernd
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experimental part
p. 142 - 151
(2010/04/29)
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- 5-PHENYL-1,3,4-OXADIAZOL-2-YL-ACETYL-4-PIPERIDINYL DERIVATIVES AS CGRP RECEPTOR ANTAGONISTS
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The present invention relates to novel compounds that are CGRP receptor antagonists, processes for their preparation, to compositions containing them and to their use in the treatment of migraine, headache, and cluster headache.
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Page/Page column 54
(2009/03/07)
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- PROCESS FOR MAKING CYTOKINE INHIBITING COMPOUNDS CONTAINING 4- AND 5- IMIDAZOLYL RINGS AND THE INTERMEDIATES THEREOF
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Disclosed are processes for making compounds containing 4- and 5-imidazolyl rings, also disclosed are the intermediates useful in the processes disclosed herein.
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Page/Page column 7
(2008/06/13)
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- Intermolecular 'oxidative' aromatic substitution reactions of the imidazol-5-yl radical mediated by the 'reductant' Bu3SnH
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The reactivity of the imidazol-5-yl in comparison to the imidazol-2-yl and phenyl radical under the reductive conditions of Bu3SnH, in intermolecular substitution reactions onto various aromatic substrates is reported. The directing effect of the hetero atom or methyl substituent in aromatic substrates was found to be more important than the polarity of the attacking σ-radical in determining the major product isomer. Graphical Abstract
- McLoughlin, Padraig T.F.,Clyne, Mairéad A.,Aldabbagh, Fawaz
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p. 8065 - 8071
(2007/10/03)
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- Imidazol-5-yl Radicals as Reactive Intermediates
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Imidazol-5-yl radicals have been generated as reactive intermediates in reduction reactions e.g. the reduction of 5-bromo-1,2-dimethylimidazole with Na/NH3/tBuOH and the reduction of 5-iodo- and 5-bromo-imidazole with Bu3SnH, to yield 1,2-dimethylimidazole.The imidazol-5-yl radical resulting from the Na/NH3/tBuOH and Bu3SnH reduction of 5-Bromo-1-(but-3-en-1-yl)-2-methylimidazole has been trapped by exo-radical cyclisation to yield the bicyclic imidazole (7).Attempted SRN1 substitution reactions between nucleophiles and 5-bromo- and 5-iodo-1,2-dimethylimidazole were unsuccessful.The radical anions of 5-nitroimidazoles were shown not to dissociate to nitrite anions and the corresponding imidazol-5-yl radicals, thereby disproving a putative explanation for the generation of nitrite anions in the antimicrobial mode of action of 5-nitroimidazoles.A mechanism has been proposed to explain the release of nitrite in the mode of action of nitroimidazoles. 13C NMR spectroscopy has been used to distinguish between 4- and 5-bromo- and -iodo-imidazoles.
- Bowman, W. Russell,Taylor, Peter F.
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p. 919 - 924
(2007/10/02)
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