865-33-8Relevant articles and documents
Evaluating Electron Transfer Reactivity of Rare-Earth Metal(II) Complexes Using EPR Spectroscopy
Moehring, Samuel A.,Evans, William J.
, p. 1187 - 1194 (2020)
To evaluate the relative reducing capacities of rare-earth metal complexes of Sc(II), Y(II), and complexes of the lanthanide metals in their +2 oxidation state, a series of reactions of trivalent LnIIIA3 compounds with divalent [Ln′IIA′3]1- complexes has been examined, where Ln = Sc, Y, or a lanthanide and A is C5H4SiMe3 (Cp′), C5H3(SiMe3)2 (Cp″), C5Me4H (Cptet), N(SiMe3)2 (NR2), 2,6-tBu2-C6H3O (OAr), or 2,6-tBu2-4-Me-C6H2O (OAr′). The specific combinations were chosen to allow evaluation by EPR spectroscopy of the Ln(II) complex. The [LnIICp′3]1- complexes of Y(II), La(II), and Lu(II) have similar reducing abilities in that they all reduce LnIIICp′3 complexes of the other metals in this group. However, these Y(II), La(II), and Lu(II) complexes all are stronger reductants than [GdIICp′3]1-, which cannot reduce LnIIICp′3 complexes of Y, La, and Lu. These results do not apply to all ligand sets, since [GdII(NR2)3]1- can reduce YIII(NR2)3 to [YII(NR2)3]1-. The amide and aryloxide complexes of Y and Sc are similar in that [YII(NR2)3]1- reduces ScIII(NR2)3 and [YII(OAr′)3]1- reduces ScIII(OAr′)3. Both [YII(NR2)3]1- and [YII(OAr′)3]1- reduce YIIICp′3. [LaIICptet3]1- has reductive capacity similar to that of [LaIICp′3]1-, and both are stronger reductants than [LaIICp″3]1-. None of the LnIII2 complexes of Sm, Tm, Dy, and Nd can reduce LnIIIA3 complexes of Y and La to [LnIIA3]1-. In the same-metal-different-ligands reactions, multiple EPR signals are found, suggesting that ligand exchange occurs alongside the electron transfer reactivity.
Aromatic Nucleophilic Substitution. XV Stopped-flow Kinetics of the Formation and Decomposition of 1,3- and 1,1-Disubstituted Meisenheimer Complexes in the Reactions of 1-Dialkylamino-2,4-dinitronaphtalenes with Potassium Methoxide in Dimethyl Sulfoxide-Methanol
Sekiguchi, Shizen,Takei, Toshio,Matsui, Kohji,Tone, Noboru,Tomoto, Noboru
, p. 3009 - 3014 (1981)
The formation of 1,3-disubstituted anionic ? complexes, followed by 1,1-disubstituted ones was confirmed by means of absorption and NMR spectra in the reactions of 1-dialkylamino-2,4-dinitronaphthalenes with potassium methoxide in DMSO-CH3OH.The rates and activation parameters were determined by kinetic studies with use of stopped-flow and conventional spectrophotometers.The rate constants for the formation of 1,3-disubstituted one decreased in the order 1-dimethylamino->1-(N-methylbutyl)amino->1-piperidino-1-diethylamino->-2,4-dinitronaphthalenes, those fot its decomposition being comparable with each other.On the other hand , the rate constant for the formation of 1,1-disubstituted one decreased in the some order as above while that for its decomposition decreased in the order 1-dimethylamino->1-(N-methylbutyl)amino->1-diethylamino->1-piperidino-2,4-dinitronaphthalenes.The mechanism was discussed from activation parameters.
METHOD FOR PRODUCING POLYALKYLENE GLYCOL DERIVATIVE HAVING AMINO GROUP AT END
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Paragraph 0162-0164; 0232, (2016/07/05)
A method simply produces a narrowly distributed and high-purity polyalkylene glycol derivative having an amino group at an end without using a heavy metal catalyst. A method for producing a polyalkylene glycol derivative having an amino group at the end by reacting a compound represented by the general formula (V) with an alkylene oxide, then reacting a reaction product with an electrophile represented by the general formula (I), and deprotecting the obtained product without using a heavy metal: [in-line-formulae]RA3O(RA4O)k-1RA4O?M+??(V)[/in-line-formulae]wherein RA3 represents a linear; branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms; RA4 represents an alkylene group having 2 to 8 carbon atoms; k represents an integer of 2 to 5; and M represents an alkali metal; wherein RA1a and RA1b each independently represent a protective group of the amino group, or one of RA1a and RA1b represents H and the other represents a protective group of the amino group, or RA1a and RA1b bind to each other to form a cyclic protective group, and the protective group is deprotectable without using a heavy metal; RA2 represents a linear, branched, or cyclic hydrocarbon group having 1 to 6 carbon atoms; and X represents a leaving group.
Preparation method for low residual granular sodium alkoxide or potassium alcoholate
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Paragraph 0025-0026, (2017/01/17)
The invention provides a preparation method for low residual granular sodium alkoxide or potassium alcoholate. The method includes using sodium or potassium and alcohol as raw materials, mixing the mixture with a solvent, reacting in inert gas atmosphere by using a microwave heating method, and removing the residual alcohol and solvent in the presence of microwave after the reaction to get the granular sodium alkoxide or potassium alcoholate. The microwave frequency is 2450 +/- 50 MHz. The method can prepare sodium alkoxide or potassium alcoholate with low residual solvent, and the prepared sodium alkoxide or potassium alcoholate is large granular solid, so that the development from powdered product to granular product can be realized, and the problems of residual solvent and potential risk troubled human for a long time can be overcome.
Process for preparation of dicarboxylic acid monoesters
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, (2008/06/13)
A process for producing a dicarboxylic acid monoester which comprises subjecting a dicarboxylic acid monoester or an alkali metal salt of a dicarboxylic acid monoester and a metal alkoxide to transesterification in the presence of an organic solvent, or a process for producing a dicarboxylic acid monoester which comprises subjecting a dicarboxylic acid monoester or an alkali metal salt of a dicarboxylic acid monoester and an alcohol to transesterification in the presence of a metal alkoxide.
Tricyclic indole-2-carboxylic acid compound used as NMDA receptor antagonist
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, (2008/06/13)
The present invention provides novel tricyclic indole-2-carboxylic acids of the following chemical formula, which have potent NMDA receptor antagonistic activity.
Decomposition of the crown ether ring in the reaction of K-, K+(15-crown-5)2 with oxetane
Grobelny, Zbigniew,Stolarzewicz, Andrzej,Maercker, Adalbert
, p. 283 - 286 (2007/10/03)
A cleavage of both oxacyclic rings occurs in the reaction of K-, K+(15-crown-5)2 with oxetane in tetrahydrofuran solution. Oxetane ring opening leads to the formation of organometallic compounds, which react with the crown molecule. Potassium methoxide, potassium n-propoxide as well as potassium tetra(ethylene glycoxide) vinyl ether are the main reaction products. It means that crown ether can act both as an activator and as a reagent under studied conditions.
Concerning the Products of the Reaction of Methyl Bromide and Ethyl Bromide with Potassium Hydroxide in Aqueous Methanolic Solutions and the Progress of this SN2-Reaction
Friedrich,Sonnefeld,Jansen
, p. 73 - 80 (2007/10/03)
Investigations of the reaction of methyl bromide and ethyl bromide with potassium hydroxide in methanolic and aqueous methanolic solutions show that the main products of these reactions are dimethyl ether and ethylmethyl ether. The reaction rates measured in methanolic or aqueous methanolic solutions are the same whether potassium hydroxide or potassium methoxide are used. These results are caused by an equilibrium between hydroxide and methoxide ions with which we could establish the equilibrium constant near 0.6. This means that a solution of sodium hydroxide c=0.1 moll-1 in methanol contains roughly 99.8% of methoxide ions. The reaction rates in methanolic as well as in aqueous methanolic solutions are strict second order. The reaction rate measured at several temperatures permitted the calculation of EA≠, ΔH≠, ΔS≠ and ΔG≠. Furthermore the kinetic investigations show that the nucleophilicity of methoxide ions is lower compared to hydroxide ions. The calculation of the Swain-Scott-parameter n results in a nucleophilicity scale in order to methoxide, hydroxide, ethoxide ions. The kinetic investigations of the reaction of ethyl bromide with methoxide and hydroxide ions in methanolic solutions demonstrate that at high temperatures the rate constant of methoxide ions is higher than that of hydroxide ions. The opposite case can be observed at lower temperatures. At the temperature of 20°C the rate constants of both reactions are equal. This is to do with the isokinetic effect which one is rarely able to observe at room temperatures.
Synthesis, properties, and structural investigations of 1,3,2-diazaborolidines and 2,3-dihydro-1H-1,3,2-diazaboroles
Schmid, Günter,Polk, Michael,Boese, Roland
, p. 4421 - 4429 (2008/10/08)
A series of variously substituted 1,3,2-diazaborolidines have been prepared by different methods. 1,3-Diisopropyl-2-methyl-1,3,2-diazaborolidine (1a), 1,3-diethyl-2-methyl-1,3,2-diazaborolidine (2a), 1-ethyl-2,3-dimethyl-1,3,2-diazaborolidine (3a), and 1,2,3-trimethyl-1,3,2-diazaborolidine (4a) are formed from the corresponding lithiated ethylenediamines and CH3BBr2 in diethyl ether (method C). 2-Methyl-1-(trimethylsilyl)-1,3,2-diazaborolidine (5a), 1-tert-butyl-2-methyl-1,3,2-diazaborolidine (6a), and 1-isopropyl-2-methyl-1,3,2-diazaborolidine (7a) can be prepared either by method C, by method A, using the ethylenediamines and H3CB[N(CH3)2]2 to eliminate HN(CH3)2, or by method B, starting with CH3BBr2, NR3, and the corresponding ethylenediamines. The unsaturated 2,3-dihydro-1H-1,3,2-diazaboroles 1b-7b are synthesized by catalytic dehydrogenation in either liquid (1b-3b) or gaseous (4b-7b) state. Diazaboroles can act as 6-π-electron donors in Cr(CO)3 complexes. 1b-4b react with (CH3CN)3Cr(CO)3 under various conditions to form the corresponding complexes 1c-4c. The monosubstituted rings 5b-7b are not suited to form stable Cr(CO)3 complexes. One of the two rings in 8 can be combined with a Cr(CO)3 fragment to give 9. The yellow 1H-1,3,2-diazaborole-tricarbonylchromium complexes 1c-4c decompose slowly at room temperature. 2,3-Dihydro-2-methyl-1,3-bis(trimethylsilyl)-1H-1,3,2-diazaborole (10) can be metalated at one N atom by NaNH2 and K(O-t-Bu) to give the salts 11a and 11b. These alkali-metal derivatives can easily be protonated by HCl or CH3OH to form the N-H derivative 5b. X-ray structure analyses have been performed on the diazaborolidines 2a and 4a and on the diazaboroles 1b, 2b, 4b, and 8. The structures of 2a and 4b have been determined at two different temperatures. 1b, 2b, and 2a crystallize in the monoclinic space groups P21/n, P21/c, and Cc, respectively. 4a crystallizes hexagonally in the space group P32; 4b, tetragonally in the space group P42. X-X-Difference electron densities of 4a, 2a, and 4b show that the B-N bonds in the saturated compounds 4a and 2a possess remarkable double-bond character. The electron distribution in the 1,3,2-diazaborole 4b corresponds with that in 6-π-electron systems.
Competition between Methoxide Attack at Ring-Carbon and at the Cyano-Group of Cyanonitroanisoles. The Effects of Cations.
Castilho, Paula C. M. F.,Crampton, Michael R.,Yarwood, Jack
, p. 2801 - 2815 (2007/10/02)
Reaction of methoxide ions with the isomeric cyanodinitroanisoles results in competition between attack at ring-carbon and at the cyano-group.Kinetic and equilibrium data are reported for reaction of 4-cyano-2,6-dinitroanisole where rapid formation of the 1,1-dimethoxy adduct is followed by slower equilibration with the imido-ester solvate.The 1,1-dimethoxy adduct is strongly stabilised by association with cations; values of the association constants decrease in the order of cations, Ba(2+) > Ca(2+) > K(+) > Na(+) > Li(+).
