- Synthesis of (POCOP)Co(Ph)(X) Pincer Complexes and Observation of Aryl-Aryl Reductive Elimination Involving the Pincer Aryl
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A series of square-planar, low-spin Co(II) and Co(III) complexes supported by the POCOP pincer ligand have been prepared for the purpose of exploring the reactions potentially involved in aryl halide coupling catalysis (POCOP = 2,6-diisopropylphosphinoxyphenyl). The investigations determined that the Co(III)-aryl intermediates of the envisioned catalytic cycle are accessible, but the desired catalysis is derailed by a C-C reductive elimination reaction that involves the POCOP ligand. Metalation of the parent (POCOP)H ligand with CoCl2 and DMAP led to the formation of (POCOP)CoCl (A-1). Metathesis of A-1 with Me3SiX reagents allowed isolation of (POCOP)CoBr (A-2), (POCOP)CoI (A-3), and (POCOP)CoOTf (A-4). Reactions of A-1 with NaOtBu, MeLi, and PhLi led to (POCOP)CoOtBu (A-5), (POCOP)CoMe (A-6), and (POCOP)CoPh (A-7). Treatment of A-1 with PhSH surprisingly led to (POCOP)CoSPh (A-8) without the need for added base. A-7 could be oxidized to (POCOP)Co(Ph)(Cl) (B-1) using N-chlorosuccinimide; however, samples of B-1 produced in this fashion were unstable with respect to decomposition to A-1. Oxidation of A-7 to (POCOP)Co(Ph)(OAc) (B-2) was accomplished with PhI(OAc)2, and metathesis of B-2 with Me3SiX produced clean samples of B-1 and (POCOP)Co(Ph)(I) (B-3) that were thermally stable. Treatment of B-1 or B-3 with NaSPh resulted in the formation of (POCOP)Co(Ph)(SPh) (B-4). Complexes B-1-B-4 are low-spin Co(III) complexes. Thermolysis of B-4, instead of the expected C-S reductive elimination, resulted in the C-C elimination with the POCOP aryl, producing (POCOP)-Ph (D-1). Hydrolysis of D-1 yielded the known 2-phenylresorcinol (D-2). The solid-state structures of A-8, B-3, and B-4 were determined by X-ray crystallography.
- Foley, Bryan J.,Palit, Chandra Mouli,Timpa, Samuel D.,Ozerov, Oleg V.
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- Synthesis of pyrenes by twofold hydroarylation of 2,6-dialkynylbiphenyls
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Cationic gold(I) complexes having Buchwald-type biarylphosphines effectively catalyzed twofold hydroarylation of 2,6-dialkynylbiphenyls to construct pyrene skeletons.
- Matsuda, Takanori,Moriya, Taisaku,Goya, Tsuyoshi,Murakami, Masahiro
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scheme or table
p. 40 - 41
(2011/05/07)
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- NOVOBIOCIN ANALOGUES AND TREATMENT OF POLYCYSTIC KIDNEY DISEASE
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Novobiocin analogues are useful in methods of treating, inhibiting, and/or preventing cyst formation in autosomal dominant polycystic kidney disease (ADPKD) in a subject. The disclosure provides methods of treating ADPKD comprising administering a therapeutically effective amount of a coumarin-3-carboxamide novobiocin analogue. Accordingly, the method can include administering a novobiocin analogue in a therapeutically effective amount for reducing levels of mTOR pathway phosphoproteins P-mTOR, P-Akt and P-S6K, or combinations thereof. Further, the method can include administering a novobiocin analogue in a therapeutically effective amount for reducing levels of Hsp-90 client proteins CFTR, ErbB2, c-Raf and Cdk4, or combinations thereof.
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- The design, synthesis, and evaluation of coumarin ring derivatives of the novobiocin scaffold that exhibit antiproliferative activity
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(Chemical Equation Presented) Novobiocin, a known DNA gyrase inhibitor, binds to a nucleotide-binding site located on the Hsp90 C-terminus and induces degradation of Hsp90-dependent client proteins at ~700 μM in breast cancer cells (SKBr3). Although many analogues of novobiocin have been synthesized, it was only recently demonstrated that monomeric species exhibit antiproliferative activity against various cancer cell lines. To further refine the essential elements of the coumarin core, a series of modified coumarin derivatives was synthesized and evaluated to elucidate structure-activity relationships for novobiocin as an anticancer agent. Results obtained from these studies have produced novobiocin analogues that manifest low micromolar activity against several cancer cell lines.
- Donnelly, Alison C.,Mays, Jared R.,Burlison, Joseph A.,Nelson, John T.,Vielhauer, George,Holzbeierlein, Jeffrey,Blagg, Brian S. J.
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experimental part
p. 8901 - 8920
(2009/04/11)
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- The dynamic covalent chemistry of mono- and bifunctional boroxoaromatics
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10-Hydroxy-10,9-boroxophenanthrene reacts rapidly and reversibly with both benzylic and alkane diols in non-polar solvents. The formation of 2:1 adducts between the boroxoaromatic and the diols is favoured. The diol component of the adduct can be exchange
- Greig, Lyndsey M.,Slawin, Alexandra M.Z.,Smith, Melanja H.,Philp, Douglas
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p. 2391 - 2403
(2007/10/03)
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- Polymer electrolyte and process for producing the same
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A polymer electrolyte having, in a main chain, a structural unit represented by the following formula (1):-[Ar1-(SO2-N-(X+)-SO2-Ar2)m-SO2-N-(X+)-SO2-Ar1-O]- wherein Ar1 and Ar2 independently represent a divalent aromatic groups, m represents an integer of 0 to 3, and X+ represents an ion selected from hydrogen ion, an alkali metal ion and ammonium ion, which is excellent in proton conductivity, thermal resistance and strength. The polymer electrolyte is soluble in solvents and has excellent film forming property and recycling efficiency.
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