Dimeric Ecdysteroid Analogues and Their Interaction with the Drosophila Ecdysteroid Receptor

2006 ◽  
Vol 71 (8) ◽  
pp. 1229-1238 ◽  
Author(s):  
Juraj Harmatha ◽  
Miloš Buděšínský ◽  
Karel Vokáč ◽  
Laurence Dinan ◽  
René Lafont
Keyword(s):  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Oxygen Atmosphere ◽  
Inert Gas ◽  
Photochemical Transformation ◽  
Dimer Formation ◽  
Ecdysteroid Receptor ◽  
Gas Atmosphere ◽  
Agonistic Activity ◽  
High Yields

Three structurally related specific ecdysteroid derivatives, 7,7'-dimers of 14-deoxy-8(14)-ene transformed 20-hydroxyecdysone, ponasterone A and ajugasterone C, were obtained by photochemical transformation. The structures of the dimeric ecdysteroids were identified mainly by NMR spectroscopy supported by MS and IR spectroscopy. Yields of the dimerisation products were dependent on the reactant concentrations and photoreaction conditions. Inert gas atmosphere supported high yields, whereas oxygen atmosphere fully prevented the dimer formation. All the three dimers retained a rather high agonistic activity at the ecdysteroid receptor in the Drosophila BII bioassay when compared with the relevant original ecdysteroids.

Catalytic activity of rhodium(I) complexes containing (ω-trimethylsilylalkyl)diphenylphosphines

1980 ◽  
Vol 45 (8) ◽  
pp. 2219-2223 ◽  
Author(s):  
Marie Jakoubková ◽  
Martin Čapka
Keyword(s):  
Catalytic Activity ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Electron Density ◽  
Phosphorus Atom ◽  
Proton Acceptor ◽  
Trimethylsilyl Group ◽  
Kinetics Of

Kinetics of homogenous hydrogenation of 1-heptene catalysed by rhodium(I) complexes prepared in situ from μ,μ'-dichloro-bis(cyclooctenerhodium) and phosphines of the type RP(C6H5)2 (R = -CH3, -(CH2)nSi(CH3)3; n = 1-4) have been studied. The substitution of the ligands by the trimethylsilyl group was found to increase significantly the catalytic activity of the complexes. The results are discussed in relation to the electron density on the phosphorus atom determined by 31P NMR spectroscopy and to its proton acceptor ability determined by IR spectroscopy.

scholarly journals (2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽  
10.3390/m1140 ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. M1140
Author(s):  
Jack Bennett ◽  
Paul Murphy
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
13C Nmr ◽  
Conjugate Addition ◽  
13C Nmr Spectroscopy ◽  
One Pot ◽  
1H And 13C Nmr ◽  
Esi Mass Spectrometry ◽  
The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

scholarly journals Recovery of Hydrogen Isotopes by Pd-coated ZrNi from Inert Gas Atmosphere Containing Impurities

2001 ◽  
Vol 38 (11) ◽  
pp. 952-958 ◽  
Author(s):  
Kan ASHIDA ◽  
Yuji HATANO ◽  
Wataru NISHIDA ◽  
Kuniaki WATANABE ◽  
Asami AMANO ◽  
...  
Keyword(s):  
Hydrogen Isotopes ◽  
Inert Gas ◽  
Gas Atmosphere

Characterization of nanomagnetites co-precipitated in inert gas atmosphere for plant nutrition

2018 ◽  
Vol 239 (1) ◽  
Author(s):  
A. Lengyel ◽  
Z. Homonnay ◽  
K. Kovács ◽  
Z. Klencsár ◽  
Sz. Németh ◽  
...  
Keyword(s):  
Plant Nutrition ◽  
Inert Gas ◽  
Gas Atmosphere

scholarly journals Isoquinolone Synthesis via Zn(OTf)2-Catalyzed Aerobic Cyclocondensation of 2-(1-Alkynyl)-benzaldehydes with Arylamines

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 683 ◽  
Author(s):  
Dost Muhammad Khan ◽  
Ruimao Hua
Keyword(s):  
Lewis Acid ◽  
Catalyst System ◽  
Oxygen Atmosphere ◽  
High Yields

A zinc(II) triflate-catalyzed cyclocondensation of ortho-alkynylbenzaldehydes with arylamines in the presence of base under an oxygen atmosphere affording isoquinolones in good to high yields has been developed. The advantages of the present catalyst system include the use of an air-stable and cheap commercially available Lewis acid as the catalyst, high atom utilization and easily available starting materials.

Pouring of steel and alloys in an inert gas atmosphere

Metallurgist ◽  
1969 ◽  
Vol 13 (1) ◽  
pp. 30-32
Author(s):  
N. S. Vachugova ◽  
N. V. Sidorov ◽  
G. A. Khasin ◽  
S. K. Filatov
Keyword(s):  
Inert Gas ◽  
Gas Atmosphere

In-depth NMR and IR study of the proton transfer equilibrium between [{(MeC(CH2PPh2)3}Ru(CO)H2] and hexafluoroisopropanol

2001 ◽  
Vol 79 (5-6) ◽  
pp. 479-489 ◽  
Author(s):  
Vladimir I Bakhmutov ◽  
Ekaterina V Bakhmutova ◽  
Natalia V Belkova ◽  
Claudio Bianchini ◽  
Lina M Epstein ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Proton Transfer ◽  
Proton Transfer Reaction ◽  
Proton Donor ◽  
Strong Hydrogen Bond ◽  
Nmr Study ◽  
Ir Study

The (carbonyl)dihydride complex [(triphos)Ru(CO)H2] (2) has been synthesized by reaction of the ruthenate [(triphos)RuH3]K (triphos = MeC(CH2PPh2)3) with ethanol saturated with CO. A single crystal X-ray analysis and IR and NMR experiments have shown that 2 adopts in both the solid state and solution an octahedral coordination geometry with a facial triphos ligand, two cis terminal hydrides, and a terminal carbonyl. The reaction of hexafluoro-2-propanol (HFIP) with 2 has been studied in CH2Cl2 solution by IR and NMR spectroscopy. The proton donor interacts with a terminal hydride of 2 forming a rather strong hydrogen bond. The resulting H-bonded adduct [{(triphos)Ru(CO)(H)H}···{HOCH(CF3)2}] (2a) has fully been characterized by in situ NMR and IR techniques. Compound 2a is in equilibrium with the nonclassical η2-H2 complex [(triphos)Ru(CO)H(H2)]+ (2b), which can independently be prepared by protonation of 2 with a strong protic acid at low temperature. Unequivocal characterization of the dihydrogen complex (2b) has been achieved by a multifaceted spectroscopic investigation (Tobs1min = 0.005 s (200 MHz), JH,D [Formula: see text] 30 Hz, DQCC = 78.3 kHz). A combined IR and NMR study of the proton transfer reaction involving 2 and HFIP in CH2Cl2 to give, first, the H-bonded adduct (2a) and, then, the dihydrogen complex (2b) has demonstrated that all these species are in equilibrium in the temperature range from 190 to 260 K. The thermodynamic parameters for the formation of 2a have independently been determined by NMR and IR methods, while those for the formation of 2b have been obtained by IR spectroscopy. An energetic profile for the reaction sequence 2 [Formula: see text] 2a [Formula: see text] 2b is proposed and discussed.Key words: hydrides, hydrogen bonding, ruthenium, IR spectroscopy, NMR spectroscopy.

scholarly journals One-Step Soft Chemical Synthesis of Magnetite Nanoparticles under Inert Gas Atmosphere. Magnetic Properties and In Vitro Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1500
Author(s):  
Laura Madalina Cursaru ◽  
Roxana Mioara Piticescu ◽  
Dumitru Valentin Dragut ◽  
Robert Morel ◽  
Caroline Thébault ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Magnetite Nanoparticles ◽  
Biomedical Applications ◽  
Magnetic Measurements ◽  
Magnetic Moments ◽  
Inert Gas ◽  
Size Analysis ◽  
Hydrodynamic Diameter ◽  
Magnetic Cores ◽  
Gas Atmosphere

Iron oxide nanoparticles have received remarkable attention in different applications. For biomedical applications, they need to possess suitable core size, acceptable hydrodynamic diameter, high saturation magnetization, and reduced toxicity. Our aim is to control the synthesis parameters of nanostructured iron oxides in order to obtain magnetite nanoparticles in a single step, in environmentally friendly conditions, under inert gas atmosphere. The physical–chemical, structural, magnetic, and biocompatible properties of magnetite prepared by hydrothermal method in different temperature and pressure conditions have been explored. Magnetite formation has been proved by Fourier-transform infrared spectroscopy and X-ray diffraction characterization. It has been found that crystallite size increases with pressure and temperature increase, while hydrodynamic diameter is influenced by temperature. Magnetic measurements indicated that the magnetic core of particles synthesized at high temperature is larger, in accordance with the crystallite size analysis. Particles synthesized at 100 °C have nearly identical magnetic moments, at 20 × 103 μB, corresponding to magnetic cores of 10–11 nm, while the particles synthesized at 200 °C show slightly higher magnetic moments (25 × 103 μB) and larger magnetic cores (13 nm). Viability test results revealed that the particles show only minor intrinsic toxicity, meaning that these particles could be suited for biomedical applications.

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