- C-H Alkylation of Aldehydes by Merging TBADT Hydrogen Atom Transfer with Nickel Catalysis
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Catalyst controlled site-selective C-H functionalization is a challenging but powerful tool in organic synthesis. Polarity-matched and sterically controlled hydrogen atom transfer (HAT) provides an excellent opportunity for site-selective functionalization. As such, the dual Ni/photoredox system was successfully employed to generate acyl radicals from aldehydes via selective formyl C-H activation and subsequently cross-coupled to generate ketones, a ubiquitous structural motif present in the vast majority of natural and bioactive molecules. However, only a handful of examples that are constrained to the use of aryl halides are developed. Given the wide availability of amines, we developed a cross-coupling reaction via C-N bond cleavage using the economic nickel and TBADT catalyst for the first time. A range of alkyl and aryl aldehydes were cross-coupled with benzylic and allylic pyridinium salts to afford ketones with a broad spectrum of functional group tolerance. High regioselectivity toward formyl C-H bonds even in the presence of α-methylene carbonyl or α-amino/oxy methylene was obtained.
- Murugesan, Vetrivelan,Ganguly, Anirban,Karthika, Ardra,Rasappan, Ramesh
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p. 5389 - 5393
(2021/07/21)
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- Dehydrogenative Coupling of Benzylic and Aldehydic C-H Bonds
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A photoinduced dehydrogenative coupling reaction between benzylic and aldehydic C-H bonds is reported. When a solution of an alkylbenzene and an aldehyde in ethyl acetate is irradiated with visible light in the presence of iridium and nickel catalysts, a coupled α-aryl ketone is formed with evolution of dihydrogen. An analogous C-C bond forming reaction occurs between a C-H bond next to the nitrogen of an N-methylamide and an aldehydic C-H bond to produce an α-amino ketone. These reactions provide a straightforward pathway from readily available materials leading to valued structural motifs of pharmacological relevance.
- Ishida, Naoki,Kawasaki, Tairin,Murakami, Masahiro
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supporting information
p. 3366 - 3370
(2020/03/06)
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- Regioselective Isomerization of 2,3-Disubstituted Epoxides to Ketones: An Alternative to the Wacker Oxidation of Internal Alkenes
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We report an alternative pathway to the Wacker oxidation of internal olefins involving epoxidation of trans-alkenes followed by a mild and highly regioselective isomerization to give the major ketone isomers in 66-98% yield. Preliminary kinetics and isotope labeling studies suggest epoxide ring opening as the turnover limiting step in our proposed mechanism. A similar catalytic system was applied to the kinetic resolution of select trans-epoxides to give synthetically useful selectivity factors of 17-23 for benzyl-substituted substrates.
- Lamb, Jessica R.,Mulzer, Michael,Lapointe, Anne M.,Coates, Geoffrey W.
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p. 15049 - 15054
(2015/12/08)
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- Synthesis of 6-substituted 3-(alkoxycarbonyl)-5-aryl-α-pyrones
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An efficient synthesis of 6-substituted 3-(alkoxycarbonyl)-5-aryl-α- pyrones is reported. This methodology consists of the successive manipulation of an addition-elimination reaction between benzyl ketone derivatives and dimethyl methoxymethylenemalonate,
- Miura, Takuya,Fujioka, Saki,Takemura, Naoto,Iwasaki, Hiroki,Ozeki, Minoru,Kojima, Naoto,Yamashita, Masayuki
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p. 496 - 502
(2014/03/21)
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- NOVEL THIENOPYRIMIDINE DERIVATIVES OR PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF, PROCESS FOR THE PREPARATION THEREOF AND PHARMACEUTICAL COMPOSITION COMPRISING THE SAME
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The present invention relates to a novel thienopyrimidine derivative having an excellent anti? inflammatory and anti-cancer activity, or a pharmaceutically acceptable salt thereof, a process for the preparation thereof and a pharmaceutical composition comprising the same. The compound according to the present invention strongly inhibits IKB kinase-β (IKK-β) involved in the activation of a transcriptional factor, NF-κB, which is associated with inducing various immune and inflammatory diseases, whereby a composition comprising the compound is a useful therapeutic agent against inflammatory diseases, in particular, arthritis and cancer.
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- Differential response of estrogen receptor subtypes to 1,3-diarylindene and 2,3-diarylindene ligands
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Estrogen receptors (ERs) control transcription of genes important for normal human development and reproduction. The signaling networks are complex, and there is a need for a molecular level understanding of the roles of receptor subtypes ERα and ERβ in normal physiology and as therapeutic targets. We synthesized two series of ER ligands, based on a common indene scaffold, in an attempt to develop compounds that can selectively modulate ER-mediated transcription. The 3-ethyl-1,2-diarylindenes, utilizing an amide linker for the 1-aryl extension, bind weakly to the ERs. The 2,3-diarylindenes bind with high affinity to the ER subtypes and demonstrate a range of different biological activities, both in transcriptional reporter gene assays and inhibition of estradiol-stimulated proliferation of MCF-7 cells. Several ligands differentiate between ERα and ERβ subtypes at an estrogen response element (ERE), displaying various levels of partial to full agonist activity at ERα, while antagonizing estradiol action at ERβ.
- Clegg, Nicola J.,Paruthiyil, Sreenivasan,Leitman, Dale C.,Scanlan, Thomas S.
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p. 5989 - 6003
(2007/10/03)
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- Estrogenic diazenes: Heterocyclic non-steroidal estrogens of unusual structure with selectivity for estrogen receptor subtypes
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Estrogens regulate many biological functions, often acting in a tissue-selective manner. Their tissue-selective action is believed to involve differential estrogen action through the two estrogen receptor (ER) subtypes, ERα and ERβ, as well as differential interaction of the ligand-receptor complexes with promoters and coregulator proteins. In the latter case, selectivity is based on the induction of specific conformations of the ligand-ER complex, conformations that are influenced by the structure of the ligand. Estrogen pharmaceuticals having an ideal balance of tissue-selective activity are being sought for menopausal hormone replacement, breast cancer prevention and therapy, and other actions. To expand on the structural diversity of ER ligands that might show such tissue selectivity, we have prepared a series of diazenes (pyrazines, pyrimidines, and pyridazines) substituted with two to four aryl groups and various short-chain aliphatic substituents. All of the pyrazine and pyrimidines bind to ER, some with high affinity and with a considerable degree of preferential binding to either ERα or ERβ. One pyrimidine and one pyrazine have ERα affinity preferences as high as 23 and 9, respectively, and one pyrimidine has an ERβ affinity preference of 8. The pyridazines, by contrast, are quite polar and have only very low binding affinity for the ER. In cell-based transcription assays, several of the pyrimidines and a pyrazine were found to be considerably more agonistic on ERα than on ERβ. Because these triaryl diazenes have the largest volumes among the ER ligands so far investigated, their high affinity demonstrates the flexibility of the ligand binding pocket of the ERs and its tolerance for large substituents. Thus, these novel heterocyclic ligands expand the repertoire of chemical structures that bind to the estrogen receptor, and they could prove to be useful in elucidating the biological behavior of the two ER subtypes and in forming the basis for new estrogen pharmaceuticals having desirable tissue selectivity.
- Ghosh, Usha,Ganessunker, Deshanie,Sattigeri, Viswajanani J.,Carlson, Kathryn E.,Mortensen, Deborah J.,Katzenellenbogen, Benita S.,Katzenellenbogen, John A.
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p. 629 - 657
(2007/10/03)
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- Synthesis and Antitumor Activity of ethane(dichloro)platinum(II) Complexes
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The complexes 1,2-diamino-1-(p-hydroxy)benzyl-1-(methyl, ethyl, and phenyl)ethane-(dichloro)platinum(II) were synthesized and characterized.The benzylic p-hydroxy group of the 1,2-diaminoethane ligand leads to good water-solubility of the complexes.The l
- Brunner, Henri,Maiterth, Friedrich,Treittinger, Barbara
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p. 942 - 946
(2007/10/02)
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