- Structure-Activity Relationship Study of Dexrazoxane Analogues Reveals ICRF-193 as the Most Potent Bisdioxopiperazine against Anthracycline Toxicity to Cardiomyocytes Due to Its Strong Topoisomerase IIβ Interactions
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Cardioprotective activity of dexrazoxane (ICRF-187), the only clinically approved drug against anthracycline-induced cardiotoxicity, has traditionally been attributed to its iron-chelating metabolite. However, recent experimental evidence suggested that the inhibition and/or depletion of topoisomerase IIβ (TOP2B) by dexrazoxane could be cardioprotective. Hence, we evaluated a series of dexrazoxane analogues and found that their cardioprotective activity strongly correlated with their interaction with TOP2B in cardiomyocytes, but was independent of their iron chelation ability. Very tight structure-activity relationships were demonstrated on stereoisomeric forms of 4,4′-(butane-2,3-diyl)bis(piperazine-2,6-dione). In contrast to its rac-form 12, meso-derivative 11 (ICRF-193) showed a favorable binding mode to topoisomerase II in silico, inhibited and depleted TOP2B in cardiomyocytes more efficiently than dexrazoxane, and showed the highest cardioprotective efficiency. Importantly, the observed ICRF-193 cardioprotection did not interfere with the antiproliferative activity of anthracycline. Hence, this study identifies ICRF-193 as the new lead compound in the development of efficient cardioprotective agents.
- Jirkovská, Anna,Karabanovich, Galina,Kube?, Jan,Skalická, Veronika,Melnikova, Iuliia,Korábe?ny, Jan,Ku?era, Tomá?,Jirkovsky, Eduard,Nováková, Lucie,Bavlovi? Piská?ková, Hana,?koda, Josef,?těrba, Martin,Austin, Caroline A.,?im?nek, Tomá?,Roh, Jaroslav
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p. 3997 - 4019
(2021/05/04)
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- CYCLIC PENTAMER COMPOUNDS AS PROPROTEIN CONVERTASE SUBTILISIN/KEXIN TYPE 9 (PCSK9) INHIBITORS FOR THE TREATMENT OF METABOLIC DISORDER
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The disclosure relates to inhibitors of PCSK9 useful in the treatment of cholesterol lipid metabolism, and other diseases in which PCSK9 plays a role, having the Formula (I):, or a pharmaceutically acceptable salt, hydrate, solvate, prodrug, stereoisomer, N-oxide, or tautomer thereof, wherein X1, R1, R2, R3, R4, R5, R6, R6', R7, R7', R8, R9, R9', R10, R11, R12, and n are described herein.
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Page/Page column 333
(2020/06/19)
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- Discovery of a stable macrocyclic o-aminobenzamide Hsp90 inhibitor which significantly decreases tumor volume in a mouse xenograft model
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An extension of our previously reported series of macrocyclic ortho-aminobenzamide Hsp90 inhibitors is reported. Addition of a second methyl group to the tether provided analogs that show increased potency in binding as well as cell-proliferation assays and, more importantly, are stable toward microsomes. We wish to disclose the discovery of a macrocycle which showed impressive biomarker activity 24-h post dosing and which demonstrated prolonged exposure in tumors. When studied in a lung cancer xenograft model, the compound demonstrated significant tumor size reduction.
- Zapf, Christoph W.,Bloom, Jonathan D.,Li, Zhong,Dushin, Russell G.,Nittoli, Thomas,Otteng, Mercy,Nikitenko, Antonia,Golas, Jennifer M.,Liu, Hao,Lucas, Judy,Boschelli, Frank,Vogan, Erik,Olland, Andrea,Johnson, Mark,Levin, Jeremy I.
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scheme or table
p. 4602 - 4607
(2011/09/15)
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- Chiral ansa-bridged η5-cyclopentadienyl molybdenum complexes: Synthesis, structure and application in asymmetric olefin epoxidation
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Ansa-bridged η5-cyclopentadienyl carbonyl molybdenum complexes were synthesized with stereogenic centers located in the side chain. An exemplary X-ray crystal structure and the catalytic activity for asymmetric olefin epoxidation are reported. In non-chiral epoxidation the compounds show a good catalytic activity, comparable to activities observed for the related non-chiral complexes of composition CpMo(CO)3X (X = Cl, CH3). For the asymmetric epoxidation of trans-β-methylstyrene the chiral induction is up to ca. 20%. The high ring strain of the ansa-bridged system hampers, unfortunately, its stability under oxidative condition.
- Zhao, Jin,Herdtweck, Eberhardt,Kühn, Fritz E.
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p. 2199 - 2206
(2007/10/03)
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- New optically active 'constrained-geometry' cyclopentadienyl-phosphine ligands and their metal complexes
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Optically active cyclopentadienyl-phosphine ligands were prepared by stereoselective ring opening of spirocyclopentadienes. Optically active metal complexes were made from these new bidentate ligands. A new stereogenic center at rhodium was generated by oxidative addition reactions with high stereoselectivity. The absolute configuration of the major isomer of one rhodium complex was determined by a X-ray structure analysis.
- Ciruelos, Santiago,Doppiu, Angelino,Englert, Ulli,Salzer, Albrecht
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p. 183 - 191
(2007/10/03)
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- Inhibition of topoisomerase II by ICRF-193, the meso isomer of 2,3-bis(2,6-dioxopiperazin-4-yl)butane: Critical dependence on 2,3-butanediyl linker absolute configuration
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The bis(2,6-dioxopiperazine)s are a structurally and mechanistically unique class of topoisomerase II inhibitors that do not bind DNA and that do not stabilize topoisomerase II-DNA strand passing intermediates ("cleavable complexes"). The most effective topoisomerase II inhibitor in the bis(2,6-dioxopiperazine) series is ICRF-193 (meso or S*, R* isomer), with a meso 2,3-butanediyl linker connecting the dioxopiperazine rings. The two enantiomeric diastereomers, (R,R) and (S,S), of ICRF-193 possessing the two optically active 2,3-butanediyl linkers have been prepared from their respective optically pure 2,4-diaminobutanes via 2,3-diaminobutane-N,N,N′,N′-tetraacetic acid, esterification, and imide formation. Both in vivo and in vitro assays for catalytic inhibition of topoisomerase II were employed to show that the (S,S)-and (R,R)-isomers are almost inactive as topoisomerase II inhibitors. The data indicate that the meso stereochemistry of the alkanediyl linker is crucial for activity and provides additional evidence that the cytotoxicity of the bis(2,6-dioxopiperazine)s is due to their ability to inhibit topoisomerase II. Copyright
- Snapka, Robert M.,Woo, Sung Ho,Blokhin, Andrei V.,Witiak, Donald T.
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p. 543 - 549
(2007/10/03)
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- PREPARATION AND 31P NMR STUDIES OF PLATINUM COMPLEXES OF SOME CHIRAL, BIDENTATE PHOSPHINES
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Two chiral diphosphines of formula RN(P(C6H5)2)2, S-peap and S-alap, have been prepared from S-α-phenethylamine and the ethyl ester of S-alanine, respectively.Their syntheses, and the preparation of the achiral diphosphine beap, N,N'-bis(diphenylphosphino)-N,N'-dibenzylethylenediamine, are described.Platinum complexes of these bidentate ligands of formula Pt(chelate)CH3Cl and ClO4 (X=acetone; p-YC5H4N, when Y=CH3, C2H5, CHO, CO2CH3, H and N(CH3)2; and a series of monodentate, Group V donor ligands, P(C2H5)3, P(C3H7)3, P(C8H17)3, PCH3(C6H5)2, P(CH3)2C6H5, P(C6H5)3, P(C6H11)(C6H5)2, P(C6H11)2C6H5, P(C6H11)3, P(C6H5)2N(C2H5)2, As(C6H5)3 and Sb(C6H5)3) have been prepared and their 1H and 31P NMR parameters recorded.The cationic pyridine complexes show a correlation of the ρ values of the para substituent to some of the 31P chemical shifts and coupling constants.The steric and electronic properties of the diphosphine ligands have been investigated by comparing their 31P NMR parameters with those of analogous complexes containing (+)-diop and S,S-chiraphos.
- Payne, Nicholas C.,Stephan, Douglas W.
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p. 203 - 222
(2007/10/02)
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