121-44-8Relevant articles and documents
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Uffer,Schlittler
, p. 1397,1399 (1948)
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Structure and dynamic behavior of phosphine gold(I)-coordinated enamines: Characterization of α-metalated iminium ions
Sriram, Madhavi,Zhu, Yuyang,Camp, Andrew M.,Day, Cynthia S.,Jones, Amanda C.
, p. 4157 - 4164 (2014)
Cationic gold(I) enamine complexes with the (t-Bu)2(o-biphenyl) phosphine ligand were isolated and characterized by NMR spectroscopy and X-ray crystallography. The complexes display highly distorted coordination modes that are consistent with characterization as α-metalated iminium ions. The barrier to rotation around the formal enamine C-C double bond has been measured in a geminally disubstituted enamine complex, and it is comparable to the barrier to C-C single-bond rotation in electronically restricted alkanes. With additional substitution on the enamine double bond, the complexes remain highly distorted, and the reaction of a mixture of E and Z enamines results in formation of a stereochemically pure gold complex. A survey of binding constants reveals enamines to be significantly stronger donors than any alkenes examined to date, and in the case of a geminally disubstituted enamine, the coordination is stronger even than that of triethylamine. The high stability drives the isomerization of an internal enamine complex generated from an intramolecular hydroamination reaction, to the exocyclic double-bond isomer.
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Lehmkuhl,H.,Reinehr,D.
, p. 215 - 220 (1973)
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Absolute rate constants for some reactions of the triethylamineboryl radical and the borane radical anion
Sheeller, Brad,Ingold, Keith U.
, p. 480 - 486 (2001)
Laser flash photolysis (LFP) of dj-tert-butyl peroxide or dicumyl peroxide at ambient temperatures in the presence of Et3N→BH3 or BH4- generated the title radicals which were found to have broad, featureless absorptions in the visible region. Rate constants for H-atom abstraction from Et3N→BH3 by cumyloxyl radicals show a small solvent dependence, e.g. 12 × 107 and 2.2 × 107 dm3 mol-1 s-1 in isooctane and acetonitrile, respectively. Rate constants for halogen atom abstraction by Et3N→BH2. and BH3.- from a number of chlorides and bromides were determined by LFP and by competitive kinetics, e.g., for Et3N→BH2. + CCl4/PhCH2Cl/CH3(CH2)2Cl, k = 4.4 × 109/1.1 × 107/5.1 × 105 dm3 mol-1 s-1 and for BH3.- + CCl4/PhCH2Cl, k = 2.0 × 109/3.0 × 107 dm3 mol-1 s-1. Rates of addition of Et3N→BH2. to 1-and 1,1-substituted olefins increase dramatically as the electron affinity of the olefin increases, confirming the nucleophilic character of amine-boryl radicals. A comparison of the present results with literature data for the addition of olefins of four nucleophilic carbon-centered radicals proves that Et3N→BH2. is by far the most nucleophilic radical for which kinetic data are available. A few rate constants for abstraction of hydrogen from electron-deficient carbon by Et3N→BH2. are also reported.
Reactions of diethylamine and ethylene catalyzed by PtII or Pt0 - Transalkylation vs. hydroamination
Dub, Pavel A.,Bethegnies, Aurelien,Poli, Rinaldo
, p. 5167 - 5172 (2011)
PtBr2/nBu4PBr (without solvent) or K 2PtCl4/NaBr (in water) have been shown to efficiently catalyze the hydroamination of ethylene by aniline and are poor catalysts for the hydroamination of ethylene by diethylamine. A DFT study on the hydroamination mechanism indicates that the energetic span of the C 2H4/Et2NH catalytic cycle is close to that of the C2H4/PhNH2 cycle. The poor performance is attributed to rapid catalyst degradation with reduction to metallic platinum. Pt0, on the other hand, catalyzes a transalkylation process, partially transforming Et2NH into Et3N, EtNH2 and NH3. This process is inhibited by C2H4. Mechanistic considerations for the Pt0-catalyzed transalkylation process are presented. Copyright
Validated HPLC and stability-indicating densitometric chromatographic methods for simultaneous determination of camylofin dihydrochloride and paracetamol in their binary mixture
Abdel Razeq, Sawsan A.,Khalil, Israa A.,Mohammd, Samah A.
, p. 2587 - 2597 (2020)
Two accurate, sensitive, precise and selective HPLC and stability-indicating TLC methods were developed for the simultaneous determination of camylofin-2HCl and paracetamol. Forced acid, alkali and oxidative degradation of camylofin-2HCl?were tried where complete degradation was achieved using 5?N HCl. HPLC method was developed to determine the mixture of the two drugs using Zorbax NH2 column and a mobile phase of 0.5percent triethylamine and pH 3.0 adjusted with 0.1percent phosphoric acid and methanol (70:30 v/v) over concentration ranges of 3–90 and 10–95?μg/mL for camylofin-2HCl and paracetamol, respectively.TLC method was used for the separation of camylofin from its acid degradate and paracetamol using chloroform–methanol–acetone–conc. ammonia (8:2:2:0.1, by volume) as developing system and band scanning at 254 nm over concentration ranges of 5–40?μg/band for camylofin-2HCl and 0.1–0.5?μg/band for paracetamol. The validation of two methods was carried out according to ICH guideline. Accuracy ranged between 98.47 and 100.67percent for the two methods with acceptable precision RSDpercent ranging between 0.66 and 1.47percent.
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Hawthorne,M.F.,Budde,W.L.
, p. 5337 (1964)
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Effects of metal particle size in gas-phase hydrogenation of acetonitrile over silica-supported platinum catalysts
Arai, Masahiko,Takada, Yoshiomi,Nishiyama, Yoshiyuki
, p. 1968 - 1973 (1998)
The gas-phase hydrogenation of acetonitrile was studied with silica-supported platinum catalysts of which the degrees of metal dispersion were widely changed by reduction conditions. The activities were found to decrease gradually during the course of reaction for all the catalysts examined. The initial rate of reaction increased with an increase in the degree of platinum dispersion, D. Triethylamine was the only main product irrespective of D and period of reaction time. The initial turnover frequency, TOF0, was shown to be smaller for larger D values. This dependence of TOF0 on D was explained by the electronic state of the surface of the platinum particles and the state of acetonitrile molecules adsorbed on them on the basis of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy measurements. The surface layer of smaller particles is more favorable for the adsorption of acetonitrile. The acetonitrile is adsorbed by platinum with the electron lone pair of nitrogen in the antibonding orbital, but electron back-donation does not takes place. As a result, the C≡N bonds of acetonitrile adsorbed on smaller particles are stronger and more difficult to hydrogenate.
High-Mobility Ions in Cyclohexane. A Transient Absorption Study
Shkrob, I. A.,Sauer, M. C.,Trifunac, A. D.
, p. 7237 - 7245 (1996)
Transient absorption kinetics in radiolysis of N2O-saturated cyclohexane has been studied (0.1 - 100 ns; 300 - 800 nm).The spectra indicate the involvement of at least three cations (ions I, II, and III), only one of them having abnormally high mobility.Ion II is probably the cyclohexene radical cation, and ion III might be the dimer olefin ion.These two ions absorb as much as ion I at 450 - 500 nm.While ion II and ion III are scavenged by ethanol and triethylamine with a rate constant of ca. 1E10 mol-1 dm3 s-1, the scavenging of ion I proceeds with rate constants of ca. 9E10 and 2.3E11 mol-1 dm3 s-1, respectively.The spectrum of ion I is similar to the spectrum of the radical cation of cyclohexane isolated in low-temperature matrices.We were not able to observe the absorption from ion I at delay times longer than 50 ns.A corresponding fast growth of the absorption from solute radical cations of pyrene and perylene was observed.The data (simulated using continuum-diffusion and Monte Carlo approaches) indicate that the scavenging constant is ca. 4E11 mol-1 dm3 s-1; the lifetime of the precursor of the aromatic radical cations is ca. 30 ns.This short lifetime cannot be explained by a reaction with radiolytic products or by homogeneous recombination, and it seems to be incompatible with identification of the long-lived high-mobility ions observed in conductivity experiments as the radical cation of cyclohexane.A mechanism in which the mobile radical cation is in equilibrium with a normally-diffusing ion is examined in an attempt to resolve this conundrum.
Ionic hydrogen bonds in bioenergetics. 4. Interaction energies of acetylcholine with aromatic and polar molecules
Deakyne, Carol A.,Meot-Ner, Michael
, p. 1546 - 1557 (1999)
The binding energies of the quaternary ions (CH3)4N+ and acetylcholine (ACh) to neutral molecules have been measured by pulsed high-pressure mass spectrometry and calculated ab initio, to model interactions in the acetylcholine receptor channel. Binding energies to C6H6 and C6H5CH3 are similar to those to H2O (33-42 kJ/mol (8-10 kcal/mol)), but are weaker than those to polar organic ligands such as CH3CO2CH3 (50-63 kJ/mol (12-15 kcal/mol)) and to amides (up to 84 kJ/mol (20 kcal/mol)). These data suggest that aromatic residues that line the groove leading to the ACh receptor site may provide stabilization comparable to water, and therefore allow entry from the aqueous environment, yet do not bind ACh as strongly as polar protein groups, and therefore allow transit, without trapping, to the receptor site. Four of the five distinct ACh conformers located computationally are stabilized by internal C-H...O hydrogen bonds involving the quaternary ammonium group, which is supported by the thermochemistry of the protonated analogue, CH3CO2CH2CH2N-(CH3) 2H+, and by the measured bonding energy between models of the ACh end groups, (CH3)4N+ and CH3CO2CH3. Each conformer forms a number of stable complexes with water or benzene. Several possible roles for an ACh conformational change upon entry into the channel are discussed, including partial compensation for the loss of bulk solvation. An additional role for the aromatic environment is also suggested, namely lowering the energy barrier to the formation of the active all-trans ACh rotamer required at the receptor site.
PHENYLPYRAZOLE COMPOUND AND METHOD FOR CONTROLLING PLANT DISEASE
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, (2021/10/22)
The present invention provides a method for controlling a plant disease which comprises applying a compound represented by formula (I) [wherein Z represents a C1-C6 chain hydrocarbon group and the like, R1 and R2 are identical to or different from each other and represent a hydrogen atom or a fluorine atom, and R3, R4, R5, R6 and R7 are identical to or different from each other and represent a C1-C6 chain hydrocarbon group and the like] to a plant or a soil, which has excellent control efficacies against plant diseases.
Catalytic Deoxygenation of Amine and Pyridine N-Oxides Using Rhodium PCcarbeneP Pincer Complexes
Tinnermann, Hendrik,Sung, Simon,Cala, Beatrice A.,Gill, Hashir J.,Young, Rowan D.
, p. 797 - 803 (2020/03/13)
Rhodium PCcarbeneP pincer complexes 1-L (L = PPh3, PPh2(C6F5), PCy3) readily facilitate deoxygenation of amine and pyridine N-oxides. The resulting complexes exhibit δ2-C= O coordination of the resulting keto POP pincer ligand. These δ2-Ca? O linkages in the metalloepoxide complexes are readily reduced by isopropyl alcohol and various benzylic alcohols. Thus, efficient catalytic deoxygenation of amine and pyridine N-oxides is possible using complexes 1-L and isopropyl alcohol. This represents a pioneering example of PCcarbeneP pincer complexes being used as catalysts for catalytic deoxygenation.
