- Nickel catalyzed α-arylation of ketones with aryltrimethylammonium triflates
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Nickel-catalyzed α-arylation of ketones involving aromatic C-N cleavage has been accomplished. Intermolecular coupling of aromatic ketones with a variety of aryltrimethylammonium triflates was achieved in the presence of Ni(COD)2, IPr·HCl, and LiOBut, giving α-arylated ketones in reasonable to excellent yields.
- Li, Jing,Wang, Zhong-Xia
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p. 7579 - 7584
(2016/08/16)
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- Bibenzyl- and stilbene-core compounds with non-polar linker atom substituents as selective ligands for estrogen receptor beta
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A series of structurally simple bibenzyl-diol and stilbene-diol core molecules, structural analogs of the well-known hexestrol and diethylstilbestrol non-steroidal estrogens, were prepared and evaluated as estrogen receptor (ER) subtype-selective ligands. Analysis of their ERα and ERβ binding showed that certain substitution patterns engendered binding affinities that were >100-fold selective for ERβ. When further investigated in cell-based gene transcription assays, some molecules showed similarly high relative transcriptional potency selectivity in favor of ERβ. Interestingly, the most ERβ-selective molecules were those bearing non-polar substituents on one of the internal carbon atoms. These compounds should be useful probes for determining the physiological roles of ERβ, and they might lead to the development of more selective and thus safer pharmaceuticals.
- Waibel, Michael,De Angelis, Meri,Stossi, Fabio,Kieser, Karen J.,Carlson, Kathryn E.,Katzenellenbogen, Benita S.,Katzenellenbogen, John A.
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experimental part
p. 3412 - 3424
(2009/10/23)
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- Antiestrogenically active 1,1,2-tris(4-hydroxyphenyl)alkenes without basic side chain: Synthesis and biological activity
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C2-Alkyl substituted derivatives of the 1,1,2-tris(4-hydroxyphenyl)ethene 3a (alkyl = Me (3b), Et (3c), Prop (3d), But (3e)) were synthesized by reaction of 1,2-bis(4-methoxyphenyl)ethanone with the appropriate alkyl halide, followed by a Grignard reaction with 4-methoxyphenylmagnesium bromide, dehydration with phosphoric acid or hydrobromic acid, and ether cleavage with BBr3. The compounds were tested for estrogen receptor (ER) binding affinity in a competition experiment with radio labeled estradiol ([3H]-E2) and for gene activation on the ER-positive MCF-7-2a cell line. All compounds showed high receptor binding affinity (RBA-value: 3b (52. 1%) > 3a (45.5%) > 3c (29.6%) > 3d (4.03%) > 3e (0.95%)). The tests on hormone dependent MCF-7-2a breast cancer cells, stably transfected with the plasmid EREwtcluc, revealed that all 1,1,2-tris(4-hydroxyphenyl)ethenes antagonized the effect of 1 nM estradiol (E2). The compounds 3b (IC50 = 15 nM) and 3c (IC50 = 10 nM) were equal in their effects to 4-hydroxytamoxifen (4OHT) (IC50 = 7 nM). Agonistic effects were low. Only 3a and 3b activated the luciferase expression (relative activation at 1 μM: 3a 60%; 3b 35%). Despite their highly antagonistic potency, the 1,1,2-tris(4-hydroxyphenyl)ethenes showed only low cytotoxic properties on the hormone sensitive MCF-7 cell line.
- Lubczyk, Veronika,Bachmann, Helmut,Gust, Ronald
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p. 1484 - 1491
(2007/10/03)
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- Photolysis of Vinyl Halides. Preferential Formation of Vinyl Cations by Copper(II) Salts
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Photolysis of vinyl halides in the presence of copper(II) salts in a significant suppression of product formation derived from vinyl radicals.Photolysis of 1,1-diaryl-2-bromopropenes in the presence of copper(II) salts yielded no 1,1-diaryl-2-propenes.Photolysis of other vinyl halides, i.e., 1,1-diaryl-2-iodopropenes, 1,1-diaryl-2-bromoethylenes, and 1-bromo-2-(p-methoxyphenyl)ethylene, also led to a large decrease in the yields of the reduced olefins derived from the vinyl radicals.Copper(II) triflate was found to be more effective for the oxidation of vinyl radicals than copper(II) acetate.These reactions are explained by the intervention of vinylcopper intermediates and the formation of vinyl cations.
- Kitamura, Tsugio,Kobayashi, Shinjiro,Taniguchi, Hiroshi
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p. 2641 - 2645
(2007/10/02)
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