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Discovery, Synthesis, and In Vitro Characterization of 2,3 Derivatives of 4,5,6,7-Tetrahydro-Benzothiophene as Potent Modulators of Retinoic Acid Receptor-Related Orphan Receptor γt. J Med Chem 2023; 66:7355-7373. [PMID: 37172324 PMCID: PMC10259452 DOI: 10.1021/acs.jmedchem.3c00021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Indexed: 05/14/2023]
Abstract
Retinoic acid receptor-related orphan receptor γt (RORγt) is a nuclear receptor that is expressed in a variety of tissues and is a potential drug target for the treatment of inflammatory and auto-immune diseases, metabolic diseases, and resistant cancer types. We herein report the discovery of 2,3 derivatives of 4,5,6,7-tetrahydro-benzothiophene modulators of RORγt. We also report the solubility in acidic/neutral pH, mouse/human/dog/rat microsomal stability, Caco-2, and MDR1-MDCKII permeabilities of a set of these derivatives. For this group of modulators, inverse agonism by steric clashes and push-pull mechanisms induce greater instability to protein conformation compared to agonist lock hydration. Independent of the two mechanisms, we observed a basal modulatory activity of the tested 2,3 derivatives of 4,5,6,7-tetrahydro-benzothiophene toward RORγt due to the interactions with the Cys320-Glu326 and Arg364-Phe377 hydrophilic regions. The drug discovery approach reported in the current study can be employed to discover modulators of nuclear receptors and other globular protein targets.
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Abstract
An efficient approach to the synthesis of previously unavailable or hardly accessible 1,2-difunctionalized cyclobutanes (mostly with NH2/NHBoc, OH, SH, or SO2F groups attached to the carbocycle either directly or via a CH2 unit) relying on the divergent strategy is described. This class of compounds provides sp3-enriched and conformationally restricted building blocks that are of special demand for medicinal chemistry. The target compounds were prepared not only as pure racemic (±)-cis- and (±)-trans-diastereomers but in some cases also as single enantiomers. The developed procedures are readily scaled up and allow obtaining the target compounds on an up to hundred-gram scale. On the basis of the results of 20 X-ray diffraction experiments, structural characterization of the 1,2-difunctionalized cyclobutane core was performed using the extended Cremer-Pople puckering parameters and exit vector (EVP) plots.
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A Ring Opening–Annulation Reaction of Anthra[1,2-d][1,2,3]triazine-4,7,12(3H)-trione in the Presence of Pyridines as an Efficient Approach to the Construction of Naphtho[2,3-H]pyrido(quinolino)[2,1-b]quinazoline System. Molecules 2022; 27:molecules27185927. [PMID: 36144663 PMCID: PMC9505032 DOI: 10.3390/molecules27185927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/06/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
The [1,2,3]triazin-4(3H)-one ring is a synthetically important molecular platform for a variety of chemical transformations. Despite this, currently, there has been little research on the reaction of the thermal opening of the [1,2,3]triazin-4(3H)-one nucleus. In this work, we describe the synthetic potential of anthra[1,2-d][1,2,3]triazine-4,7,12(3H)-trione in the reaction of the thermal opening of a cycle following the [4+2]-cycloaddition reaction with a number of pyridine derivatives and quinoline. It is shown that this method is effective for the synthesis of the 6H-naphtho[2,3-H]pyrido(quinolino)[2,1-b]quinazoline-6,9,14-trione system. We also investigate the influence of the position of substituents in the structure of pyridine on the formation characteristics of the target products.
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Trianionic 1,3,2‐Dioxaborine‐Containing Polymethines: Bright Near‐Infrared Fluorophores. Chemistry 2022; 28:e202202168. [DOI: 10.1002/chem.202202168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Indexed: 11/08/2022]
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5
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Thiacalix[4]arene phosphoric acids. Synthesis, structure, and inhibition of glutathione S-transferases. PHOSPHORUS SULFUR 2022. [DOI: 10.1080/10426507.2021.2011877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Novel convenient approach to 1,4,2-benzodithiazine-1,1-dioxides and 1,2,3-benzoxathiazine-2,2-dioxides. ARKIVOC 2022. [DOI: 10.24820/ark.5550190.p011.765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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7
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‘Hybrid’ mero-anionic polymethines with a 1,3,2-dioxaborine core. NEW J CHEM 2022. [DOI: 10.1039/d1nj05104k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and characterization of new mero-anionic polymethines of the D–π–A–π–A′ type are described.
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Abstract
The difluoroboron β-diketonate ring is ever more used for creating bright polymethine-type fluorophores for the visible and NIR range. Here, we report the synthesis and spectral properties of a series of dianionic cyanine dyes of the rare A1-π-A-π-A1 type, with the central dioxaborine ring (A) embedded into the polymethine chain and various electron-acceptor terminal groups A1. Depending on the nature of the end group, the maxima of their intensive (with molar extinctions up to 380 000 M-1 cm-1) and narrow long-wavelength absorption band lie in the range of 530-770 nm. Their absorption and fluorescence bands are nearly mirror-like and characterized by weak solvatochromism; the marked hypsochromic shifts are observed only when going from polar aprotic solvents to methanol. The designed dianionic dyes have fluorescence quantum yields up to 92 % in the visible range, and even for the NIR dyes, the values of 18-37 % are observed in DMF.
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Abstract
We found that 1-phosphanyl-1,2,3,4-tetrahydroquinazolines undergo ring enlargement. Their treatment with trifluoroacetic or hydrochloric acid afforded diazaphosphepinium salts. Deprotonation of these salts gave the corresponding neutral diazaphosphepines. The reaction of 1-phosphanyl-1,2,3,4-tetrahydroquinazolines with diazomethane or phenylazide afforded triazaphosphocine derivatives via insertion of P-N moiety. At the same time, an analogous hexahydropyrimidine derivative reacted with phenylazide in a normal manner at the phosphorus atom to afford the P(V) derivative.
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Abstract
A method for the synthesis of iodomethyl-substituted five-membered sultams has been developed. The sultams were synthesized by intramolecular iodoamination of alkenyl sulfamides. The method allows synthesis of N- and C-substituted sultams. NH-Sultams were prepared by acidic cleavage of the corresponding tert-butyl sultams that are readily available. Varying the length of alkenyl substituent at sulfamide it was shown that only five- and six-membered sultams could be prepared by this method. Neither four- nor seven-membered sultams were detected. The simple practical procedure and available starting materials make the variously substituted sultams readily available.
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Twisting and Turning the Sulfonamide Bond: A Synthetic, Quantum Chemical, and Crystallographic Study. J Org Chem 2020; 85:5288-5299. [PMID: 32162518 DOI: 10.1021/acs.joc.9b03394] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Structural restriction of the sulfonamide bond was used to design sultams with abnormal geometric parameters. Based on analysis of tertiary aliphatic sulfonamides published in the Cambridge crystallographic database, Paquette's sultams (i.e., bridged bicyclic sultams with a bridgehead nitrogen atom) were outlined, and a number of these compounds (including the novel smallest representative, 2-thia-1-azabicyclo[2.1.1]hexane 2,2-dioxide) were synthesized by cyclization of the corresponding amino sulfonyl fluorides. A series of tertiary aliphatic sulfonamides was studied by crystallographic and quantum chemical methods. It was found that the s-character of the nitrogen lone pair is the most important factor defining properties of the S-N bond. Thus, going from the sp3-hybrid lone pair in common sulfonamides to the sp-like lone pair in the smallest Paquette's sultam resulted in an increase in S-N bond length by ca. 0.06 Å. The strain energy of ca. 30 kcal/mol was predicted for the latter compound, which was higher than for any existing sulfonamides studied.
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Anthra[1,2- d][1,2,3]triazine-4,7,12(3 H)-triones as a New Class of Antistaphylococcal Agents: Synthesis and Biological Evaluation. Molecules 2019; 24:molecules24244581. [PMID: 31847306 PMCID: PMC6943585 DOI: 10.3390/molecules24244581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/06/2019] [Accepted: 12/12/2019] [Indexed: 12/12/2022] Open
Abstract
The development and spread of resistance of human pathogenic bacteria to the action of commonly used antibacterial drugs is one of the key problems in modern medicine. One of the especially dangerous and easily developing antibiotic resistant bacterial species is Staphylococcus aureus. Anthra[1,2-d][1,2,3]triazine-4,7,12(3H)-triones 22-38 have been developed as novel effective antistaphylococcal agents. These compounds have been obtained by sequential conversion of 1-amino-9,10-dioxo-9,10-dihydroanthracene-2-carboxylic acid (1) and 1-amino-4-bromo-9,10-dioxo-9,10-dihydroanthracene-2-carboxylic acid (2) into the corresponding amides 5-21, followed by subsequent endo-cyclization under the influence of sodium nitrite in acetic acid. Evaluation of the antimicrobial activity of the synthesized compounds against selected species of Gram-positive and Gram-negative bacteria as well as pathogenic yeasts of the Candida genus has been carried out by the serial dilution method. It has been established that anthra[1,2-d][1,2,3]triazine-4,7,12(3H)-triones exhibit selective antibacterial activity against Gram-positive bacteria. Eight, six and seven, out of seventeen compounds tested, effectively inhibited the growth of S. aureus ATCC 25923, S. aureus ATCC 29213 and S. epidermidis ATCC12228, respectively, at a concentration equal to 1 µg/mL or lower. The high antistaphylococcal potential of the most active compounds has been also confirmed against clinical isolates of S. aureus, including the MRSA strains. However, bacteria of the Staphylococcus genus have demonstrated apparent resistance to the novel compounds when grown as a biofilm. None of the four selected compounds 3234 and 36 at a concentration of 64 µg/mL (128 or 256 × MIC-against planktonic cells) has caused any decrease in the metabolic activity of the staphylococcal cells forming the biofilm. The kinetic time-kill assay revealed some important differences in the activity of these substances. Compound 33 is bacteriostatic, while the other three demonstrate bactericidal activity.
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Synthesis and chemical properties of Di(2-fluoro-2-polyfluoroalkyl- alkenyl)sulfides and 2,6-bis(polyfluoroalkyl)-1,4-oxathiine 4,4-dioxides. J Sulphur Chem 2019. [DOI: 10.1080/17415993.2019.1596269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Abstract
N-Cbz- and N-Boc-protected exo-spiro[oxirane-3,2′-tropanes] were selectively synthesized via either epoxidation or hydroxybromination/dehydrobromination of the corresponding alkenes.
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15
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A bio-inspired approach to proline-derived 2,4-disubstituted oxazoles. HETEROCYCL COMMUN 2018. [DOI: 10.1515/hc-2017-0235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
A convenient four-step approach to the synthesis of (S)-4-alkyl-2-(pyrrolidin-2-yl)oxazoles starting from l-Boc-proline inspired by naturally occurring oxazole-containing peptidomimetics is described. The key step is the cyclization of 1-Boc-N-(1-oxoalkan-2-yl)pyrrolidine-2-carboxamides – aldehyde intermediates which demonstrate low to moderate stability – under Appel reaction conditions. This method furnishes the target compounds with more than 98% ee and in a 17–51% overall yield and has been used at up to a 45-g scale.
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Synthesis of fused heterocycles from 2-aryl-5-(chlorosulfonyl)-1,3-oxazole-4-carboxylates and α-aminoazoles involving the Smiles rearrangement. CURRENT CHEMISTRY LETTERS 2018. [DOI: 10.5267/j.ccl.2018.9.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Front Cover Picture: Gram-Scale Synthesis of Amines Bearing a gem
-Difluorocyclopropane Moiety (Adv. Synth. Catal. 18/2017). Adv Synth Catal 2017. [DOI: 10.1002/adsc.201701120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Beyond the Five and Six: Evaluation of Seven-Membered Cyclic Anhydrides in the Castagnoli–Cushman Reaction. Org Lett 2016; 19:130-133. [PMID: 28001424 DOI: 10.1021/acs.orglett.6b03426] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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An Expedient and Practical Approach to Functionalized 3-Aza-, 3-Oxa-, and 3-Thiabicyclo[3.3.1]nonane Systems. SYNTHESIS-STUTTGART 2014. [DOI: 10.1055/s-0034-1379456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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[1,3]Thiazolo[2′,3′:3,4][1,2,4]triazolo[1,5-a]pyrimidines - A New Heterocyclic System Accessed via Bromocyclization. J Heterocycl Chem 2014. [DOI: 10.1002/jhet.2073] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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22
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Tetra-chloridodi-μ3-oxido-tetra-kis-(μ2-propan-2-olato-κ(2) O:O)ditin(II)ditin(IV). Acta Crystallogr Sect E Struct Rep Online 2014; 70:m45-6. [PMID: 24764816 PMCID: PMC3998255 DOI: 10.1107/s1600536814000816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 01/13/2014] [Indexed: 11/25/2022]
Abstract
The centrosymmetric tetranuclear title molecule, [Sn4(C3H7O)4Cl4O2], contains two types of Sn atoms, SnII and SnIV. The SnII atom has a trigonal–pyramidal coordination environment and is bonded to two O atoms from two isopropanolate groups and one μ3-oxide atom. The SnIV atom has an octahedral coordination environment, formed by two chloride atoms, two μ3-oxide atoms and two O atoms from isopropanolate groups.
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Bis(μ-propan-2-olato-κ 2O: O)bis[chlorido(propan-2-ol-κ O)bis(propan-1-olato-κ O)tin(IV)]. Acta Crystallogr Sect E Struct Rep Online 2012; 68:m337-8. [PMID: 22412469 PMCID: PMC3297279 DOI: 10.1107/s1600536812007799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 02/21/2012] [Indexed: 11/18/2022]
Abstract
The binuclear centrosymmetric title compound, [Sn2(C3H7O)6Cl2(C3H8O)2], exhibits an edge-shared double octahedral exhibits an edge-shared octahedral structure, which is distorted owing to the presence of asymmetric intramolecular hydrogen bonds between the axially coordinated isopropanol and isopropoxide ligands. The H atom of the hydroxy group is located nearer to an isopropoxy group with the longest Sn—O bond [2.1789 (17) Å].
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(N,N,N',N'-Tetra-methyl-ethylenediamine-κN)bis-(2,4,6-trimethyl-phenolato-κO)germanium(II). Acta Crystallogr Sect E Struct Rep Online 2012; 68:m296. [PMID: 22412439 PMCID: PMC3297249 DOI: 10.1107/s160053681200503x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 02/05/2012] [Indexed: 11/10/2022]
Abstract
In the title compound, [Ge(C(9)H(11)O)(2)(C(6)H(16)N(2))], the Ge(II) atom is coordinated in a distorted trigonal-pyramidal geometry by two O atoms belonging to two 2,4,6-trimethyl-phenolate ligands and one N atom of a tetra-methyl-ethylenediamine ligand. Comparing the structure with published data of similar compounds shows that the Ge-O bonds are covalent and the Ge-N bond is coordinated.
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Regioselective Annulation of Seven-, Eight-, and Nine-Membered Azaheterocycles to Benzimidazole Starting from Chloro-Substituted 2-Aza-1,3-dienes. SYNTHESIS-STUTTGART 2006. [DOI: 10.1055/s-2006-942453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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28
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The Very Covalent Diammino(o-benzoquinonediimine) Dichlororuthenium(II). An Example of Very Strong π-Back-Donation. Inorg Chem 2006; 45:6246-62. [PMID: 16878934 DOI: 10.1021/ic060220z] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The syntheses and X-ray structures of the complexes Ru(S-dmso)Cl2(opda) (1) and Ru(NH3)2Cl2(bqdi) (2) are described (opda= o-phenylenediamine, bqdi= o-benzoquinonediimine). Optical absorption and emission, vibrational (resonance Raman), and electrochemical data are discussed. We explore the nature of the ruthenium benzoquinone electronic interaction in species 2 primarily within the framework of density functional theory (DFT) but also using INDO/S to extract Coulombic and exchange integrals. The resonance Raman and emission data were understood in terms of a common set of coupled vibrations localized primarily within the ruthenium metallacycle ring. Experimental and computational data were also compared among a select group of ruthenium bqdi species with other spectator ligands, specifically ammonia, 2,2'-bipyridine, and 2,4-pentanedione. The changes in the electrochemistry, optical spectroscopy, and vibrational spectra with changing spectator ligand donicity were explained within a common theoretical (DFT) model which further provided a detailed analysis of the variation in the molecular orbital descriptions. With the application of an extended charge decomposition analysis (ECDA), a detailed picture emerged of the bonding between the bqdi ligand and the metal atom, illustrating the coupling between the orbitals of each fragment as a function of orbital symmetry and charge transfer between the fragments of the complex. Metal-to-bqdi pi-back-donation is seen to be very important.
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Aminoalkylation of ‘Push-Pull’ Enamines Having a Methyl Group at the α-Position with Imines of Methyl 3,3,3-Trifluoropyruvate. SYNTHESIS-STUTTGART 2006. [DOI: 10.1055/s-2006-926457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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30
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The tert-Amino Effect in the Synthesis of Hetaryl- and Arylsulfonyl-Substituted Pyrrolo- and Pyrido[1,2-a]quinoline Derivatives and their Pyrazolo Annulated Analogues. SYNTHESIS-STUTTGART 2005. [DOI: 10.1055/s-2005-870004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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31
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Protonated nucleobase ligands: synthesis, structure and characterization of 9-methyladeninium hexachloroplatinate and pentachloro(9-methyladeninium)platinum(IV). J Inorg Biochem 2004; 98:439-46. [PMID: 14987844 DOI: 10.1016/j.jinorgbio.2003.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Revised: 11/24/2003] [Accepted: 12/01/2003] [Indexed: 10/26/2022]
Abstract
Na(2)[PtCl(6)] was found to react with (9-MeAH)Cl(.)H(2)O (2) (9-MeA=9-methyladenine) in aqueous solution yielding (9-MeAH)(2)[PtCl(6)](.)2H(2)O (3). The same compound was obtained from hexachloroplatinic acid and 9-methyladenine. Performing this reaction at 60 degrees C, complex formation took place yielding the 9-methyladeninium complex [PtCl(5)(9-MeAH)](.)2H(2)O (4a). An analogous complex, [PtCl(5)(9-MeAH)](.)1/2(18C6)(.)H(2)O (4b, 18C6=crown ether 18-crown-6), was formed in the reaction of aquapentachloroplatinic acid (H(3)O)[PtCl(5)(H(2)O)](.)2(18C6)(.)6H(2)O (1) with 9-methyladenine in 1:1 ratio. All complexes were isolated in moderate to good yields as yellow powder (4b) and crystals (3, 4a), respectively. They were fully characterized by microanalysis, IR and NMR ((1)H, (13)C, (195)Pt) spectroscopies, and in part (2, 3, 4a) also by single-crystal X-ray diffraction analysis. Molecular structure of complex 4a exhibited that the 9-methyladeninium ligand is N1 protonated and coordinated through N7 to platinum(IV).
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Synthesis, Characterization, and Reactivity of (Fluoroalkyl)- and (Fluorocycloalkyl)cobaloximes: Molecular Structure of a (2-Fluorocyclohexyl)cobaloxime Complex and Hindered Rotation of 2-Fluorocycloalkyl Ligands. Organometallics 2003. [DOI: 10.1021/om030525a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Synthese und Charakterisierung von symmetrisch und unsymmetrisch substituierten binuklearen Ethylrhodoximen mit neutralen zweizähnigen N-, S- und P-Brückenliganden. Z Anorg Allg Chem 2003. [DOI: 10.1002/zaac.200300060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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34
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Synthesis, crystal structures and electronic properties of imidazoline nitroxide radicals bearing active groups in electropolymerisation. NEW J CHEM 2003. [DOI: 10.1039/b208762f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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36
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Synthese und Charakterisierung von 2-O-funktionalisierten Ethylrhodoximen und -cobaloximen. Z Anorg Allg Chem 2002. [DOI: 10.1002/1521-3749(200211)628:11<2375::aid-zaac2375>3.0.co;2-q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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37
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Synthesis, structure, and magnetic properties of the single-molecule magnet [Ni(21)(cit)(12)(OH)(10)(H(2)O)(10)](16-). Inorg Chem 2002; 41:5133-40. [PMID: 12354047 DOI: 10.1021/ic020252w] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The preparation of two new compounds containing the cluster [Ni(21)(cit)(12)(OH)(10)(H(2)O)(10)](16-) is presented, together with a detailed magnetic investigation of one of the compounds. We found that this cluster shows an unexpected stability and that it exists as different stereoisomers. Compound 1 contains the achiral cluster with a Delta-Lambda configuration, and compound 2 contains a pair of enantiomeric clusters with the configurations Delta-Delta and Lambda-Lambda, respectively. Magnetic measurements of 1 in the millikelvin range were necessary to determine the spin ground state of S = 3, and they also revealed a magnetic anisotropy within the ground state. A frequency-dependent out-of-phase signal was found in alternating current susceptibility measurements at very low temperatures, which indicates a slow relaxation of the magnetization. Thus, individual molecules are acting as single magnetic units, which is a rare phenomenon for nickel clusters. The energy barrier exhibited by compound 1 has been calculated to be 2.9 K.
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Ferromagnetism and chirality in two-dimensional cyanide-bridged bimetallic compounds. Inorg Chem 2002; 41:4615-7. [PMID: 12206680 DOI: 10.1021/ic0257219] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The combination of hexacyanoferrate(III) anions, [Fe(CN)(6)](3)(-), with nickel(II) complexes derived from the chiral ligand trans-cyclohexane-1,2-diamine (trans-chxn) affords the enantiopure layered compounds [Ni(trans-(1S,2S)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2)O (1) and [Ni(trans-(1R,2R)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2)O (2). These chiral systems behave as ferromagnets (T(c) = 13.8 K) with a relatively high coercive field (H(c) = 0.17 T) at 2 K. They also exhibit an unusual magnetic behavior at low temperatures that has been attributed to the dynamics of the magnetic domains in the ordered phase.
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New diphosphine ligands containing ethyleneglycol and amino alcohol spacers for the rhodium-catalyzed carbonylation of methanol. Chemistry 2002; 8:3343-52. [PMID: 12203315 DOI: 10.1002/1521-3765(20020802)8:15<3343::aid-chem3343>3.0.co;2-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The new diphosphine ligands Ph(2)PC(6)H(4)C(O)X(CH(2))(2)OC(O)C(6)H(4)PPh(2) (1: X=NH; 2: X=NPh; 3: X=O) and Ph(2)PC(6)H(4)C(O)O(CH(2))(2)O(CH(2))(2)OC(O)C(6)H(4)PPh(2) (5) as well as the monophosphine ligand Ph(2)PC(6)H(4)C(O)X(CH(2))(2)OH (4) have been prepared from 2-diphenylphosphinobenzoic acid and the corresponding amino alcohols or diols. Coordination of the diphosphine ligands to rhodium, iridium, and platinum resulted in the formation of the square-planar complexes [(Pbond;P)Rh(CO)Cl] (6: Pbond;P=1; 7: Pbond;P=2; 8: Pbond;P=3), [(Pbond;P)Rh(CO)Cl](2) (9: Pbond;P=5), [(P-P)Ir(cod)Cl] (10: Pbond;P=1; 11: Pbond;P=2; 12: Pbond;P=3), [(Pbond;P)Ir(CO)Cl] (13: Pbond;P=1; 14: Pbond;P=2; 15: Pbond;P=3), and [(Pbond;P)PtI(2)] (18: Pbond;P=2). In all complexes, the diphosphine ligands are trans coordinated to the metal center, thanks to the large spacer groups, which allow the two phosphorus atoms to occupy opposite positions in the square-planar coordination geometry. The trans coordination is demonstrated unambiguously by the single-crystal X-ray structure analysis of complex 18. In the case of the diphosphine ligand 5, the spacer group is so large that dinuclear complexes with ligand 5 in bridging positions are formed, maintaining the trans coordination of the P atoms on each metal center, as shown by the crystal structure analysis of 9. The monophosphine ligand 4 reacts with [[Ir(cod)Cl](2)] (cod=cyclooctadiene) to give the simple derivative [(4)Ir(cod)Cl] (16) which is converted into the carbonyl complex [(4)Ir(CO)(2)Cl] (17) with carbon monoxide. The crystal structure analysis of 16 also reveals a square-planar coordination geometry in which the phosphine ligand occupies a position cis with respect to the chloro ligand. The diphosphine ligands 1, 2, 3, and 5 have been tested as cocatalysts in combination with the catalyst precursors [[Rh(CO)(2)Cl](2)] and [[Ir(cod)Cl](2)] or [H(2)IrCl(6)] for the carbonylation of methanol at 170 degrees C and 22 bar CO. The best results (TON 800 after 15 min) are obtained for the combination 2/[[Rh(CO)(2)Cl](2)]. After the catalytic reaction, complex 7 is identified in the reaction mixture and can be isolated; it is active for further runs without loss of catalytic activity.
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Synthesis, characterization, and structure of [[PtMe(3)(9-MeA)](3)] (9-MeAH = 9-Methyladenine): a cyclic trimeric platinum(IV) complex with a nucleobase. Inorg Chem 2002; 41:2667-71. [PMID: 12005490 DOI: 10.1021/ic0110530] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of [[PtMe(3)I](4)] with AgOAc in acetone results in formation of trimethylplatinum(IV) acetate (1) that reacts with 9-methyladenine (9-MeAH) in ratio 1:1 with its deprotonation yielding a trimethyl(9-methyladeninato)platinum(IV) complex (2) that was obtained from acetone/diethyl ether as [[PtMe(3)(9-MeA)](3)] x Me(2)CO (2a) and from chloroform/diethyl ether as [[PtMe(3)(9-MeA)](3)] x 1.5Et(2)O x 2H(2)O (2b). Single-crystal X-ray investigations revealed that 2a and 2b in the solid state form cyclic trimeric molecules in which three PtMe(3) moieties are bridged by deprotonated 9-methyladenine ligands in mu-kappa N(1):kappa(2)N(6),N(7) coordination mode. The methyladeninato ligands include angles with the plane defined by the Pt(3) unit between 55.9(3) degrees and 66.6(3) degrees. Thus, the structures of the cyclic trimers resemble hollow truncated cones. Crystals of the acetone solvate 2a consist of stacks of unidirectional trimeric molecules; the solvate acetone molecules lie between the trimers. In the crystals of complex 2b, the trimeric molecules are arranged head-to-head, and the cavity between is filled with four water molecules. Complex 2 was also fully characterized by (1)H, (13)C, and (195)Pt NMR spectroscopies. The existence of the cyclic trimeric structure of complex 2 in acetone solution was confirmed by ESI mass spectrometry exhibiting the protonated trimeric complex [[tMe(3)(9-MeA)]3)H](+) [2 + H](+) (m/z 1165) as base peak. CID experiments of that parent ion showed as main fragmentation processes loss of two methyl ligands (probably as ethane) and cleavage of a methyladenine ligand.
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Ruthenium(ii) complex of bis(2,2′-bipyridine)(6,7-dicyanodipyrido[3,2-a:2′,3′-c]phenazine): synthesis, structure, electrochemical and luminescence studies. ACTA ACUST UNITED AC 2002. [DOI: 10.1039/b210440g] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Different fluoride anion sources and (trifluoromethyl)trimethylsilane: molecular structure of tris(dimethylamino)sulfonium bis(trifluoromethyl)trimethylsiliconate, the first isolated pentacoordinate silicon species with five Si–C bonds. Chem Commun (Camb) 1999. [DOI: 10.1039/a901953g] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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The First Examples of Donor-Stabilized Phosphanetriyl-Phosphonium [RP2] Ions. PHOSPHORUS SULFUR 1996. [DOI: 10.1080/10426509608054829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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CRYSTAL AND MOLECULAR STRUCTURE OF A THALLIUM(I) BENZOYLCYANOXIMATE COMPLEX WITH 18-CROWN-6. J COORD CHEM 1995. [DOI: 10.1080/00958979508024315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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[Differences in the enzymatic activity of mitochondria from enriched neuronal and glial fractions]. UKRAINS'KYI BIOKHIMICHNYI ZHURNAL 1976; 48:215-22. [PMID: 181884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Studies were performed in the activities of certain enzymes from oxidoreductase group: cytochrome c-oxidoreductase (EC 1.6.99.3), succinate dehydrogenase succinates: cytochrome c-oxidoreductase (EC 1.3.99.1), cytochrome oxidase (EC 1.9.3.1) and malate dehydrogenase (EC 1.1.1.37) in mitochondria from neuronal and glial-enriched fractions. The mitochondrial fraction purity was observed by the electron microscope. The enzyme activity of the glial mitochondrial fraction was much higher than that in the neuronal mitochondria. Malate dehydrogenase from glial enriched fraction consists of three isoenzymes, while neuronal mitochondria had two isoenzymes of malate dehydrogenase. The neuronal mitochondria were found to be more stable to lubrol and digitonin.
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