Acridone studies. XI. Reaction of some Polyalkoxy-10-methylacridones with sodium methoxide in methanol and in dimethyl sulphoxide

1972 ◽  
Vol 25 (8) ◽  
pp. 1751 ◽  
Author(s):  
DKC Hodgeman ◽  
RH Prager
Keyword(s):  
Sodium Methoxide ◽  
Activation Parameters ◽  
Dimethyl Sulphoxide ◽  
Aromatic Nucleus ◽  
Methylene Group

The isomeric dimethoxymethylenedioxy-10-methylacridone react with sodium methoxide in methanol to give a number of products which have been characterized. Substitution occurs on both the aromatic nucleus and the methylene group. In dimethyl sulphoxide opening of the methylenedioxy ring occurs exclusively and the rates and activation parameters of this reaction have been measured.

Phosphonium salts. III. The action of cyanide ion and other nucleophiles on some bis-phosphonium salts

1969 ◽  
Vol 22 (7) ◽  
pp. 1405 ◽  
Author(s):  
JJ Brophy ◽  
MJ Gallagher
Keyword(s):  
Sodium Azide ◽  
Sodium Methoxide ◽  
Sodium Acetate ◽  
Potassium Cyanide ◽  
Dimethyl Sulphoxide ◽  
High Yield ◽  
Phosphonium Salts ◽  
Elimination Reaction ◽  
Cyanide Ion ◽  
Reaction Proceeds

Cyclic and acyclic bis-phosphonium salts with a two-carbon bridge are smoothly cleaved to phosphines in high yield by potassium cyanide in dimethyl sulphoxide. Evidence is presented that the reaction proceeds by an elimination-addition sequence. An elimination reaction also occurs when sodium methoxide, sodium azide, sodium acetate, and triethylamine react with ethane-1,2-bis(tri-phenylphosphonium) dibromide. ��� In a novel reaction, triphenylphosphine is converted into its oxide by a mixture of sodium azide and dimethyl sulphoxide.

Acridone studies. X. Reactions of the isomeric Bromo-10-methylacridones with sodium methoxide in methanol and in dimethyl sulphoxide

1972 ◽  
Vol 25 (3) ◽  
pp. 585 ◽  
Author(s):  
DKC Hodgeman ◽  
RH Prager
Keyword(s):  
Sodium Methoxide ◽  
Dimethyl Sulphoxide ◽  
Radical Chain

The isomeric 1-, 2-, 3-, and 4-bromo-10-methylacridones undergo a radical chain reduction to 10-methylacridone in the presence of sodium methoxide in methanol. Evidence for the mechanism is presented. In the presence of methanol-free dimethyl sulphoxide, the 1- and 3-bromo-10-methylacridones are cleanly converted by sodium methoxide into the respective methoxy compounds, and the rates have been measured at 40�. In the same solvent, the 2- and 4-bromo isomers are again reduced by sodium methoxide.

Kinetics and Mechanism of Oxidation of Aliphatic Secondary Alcohols by Benzimidazolium Fluorochromate in Dimethyl Sulphoxide Solvent

2021 ◽  
Vol 37 (3) ◽  
pp. 626-633
Author(s):  
Bhawana Arora ◽  
Jitendra Ojha ◽  
Pallavi Mishra
Keyword(s):  
Activation Parameters ◽  
Sigmatropic Rearrangement ◽  
Dimethyl Sulphoxide ◽  
Secondary Alcohols ◽  
Hydrogen Ions ◽  
Reaction Conditions ◽  
First Order Kinetics ◽  
Aqueous Solvent ◽  
Ester Formation ◽  
Different Temperatures

Oxidation of secondary alcohols is an important part of synthetic organic chemistry. Various studies are carried out at different reaction conditions to determine the best mechanistic pathways. In our study, oxidation of different secondary alcohols was done by using Benzimidazolium Fluorochromate in Dimethyl Sulphoxide, which is a non-aqueous solvent. Oxidation resulted in the formation of ketonic compounds. The reaction showed first order kinetics both in BIFC and in the alcohols. Hydrogen ions were used to catalyze the reaction. We selected four different temperatures to carry out our study. The correlation within the activation parameters like enthalpies and entropies was in accordance with the Exnerʼs criterion. The deuterated benzhydrol (PhCDOHPh) oxidation exhibited an important primary kinetic isotopic effect (kH / kD = 5.76) at 298 K. The solvent effect was studied using the multiparametric equations of Taft and Swain. There was no effect of addition of acrylonitrile on the oxidation rate. The mechanism involved sigmatropic rearrangement with the transfer of hydrogen ion taking place from alcohol to the oxidant via a cyclic chromate ester formation.

Electron-transfer reactions in non-aqueous media. II. Reduction of CoF(NH3)52+, CoCl(NH3)52+ and CoBr(NH3)52+ by iron(II) in dimethyl sulphoxide-water mixtures

1976 ◽  
Vol 29 (1) ◽  
pp. 97 ◽  
Author(s):  
BA Matthews ◽  
DW Watts
Keyword(s):  
Electron Transfer ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Solvent Composition ◽  
Dimethyl Sulphoxide ◽  
Transfer Reactions ◽  
Octahedral Coordination ◽  
Electron Transfer Reactions ◽  
Kinetics Of

The kinetics of the reduction of the cobalt(111) octahedral complexes, CoF(NH3)52+, CoCl(NH3)52+ and CoBr(NH3)52+, by iron((11) in various Me2SO-H2O mixtures have been studied over a range of temperatures. The activation parameters obtained for the chloro and bromo systems are consistent with a change in the stereochemistry of the iron (11) atom in the bridged intermediate from octahedral in water to tetrahedral with increasing Me2SO concentration. The fluoro system, however, has activation parameters which are less sensitive to solvent composition and consistent with the iron(11) atom maintaining octahedral coordination.

Primary isotope effects and mechanism of base initiated β-elimination reactions of di-(p-nitrophenyl)fluoroethanes

1977 ◽  
Vol 55 (10) ◽  
pp. 1696-1700 ◽  
Author(s):  
Jan Kurzawa ◽  
Kenneth T. Leffek
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Sodium Methoxide ◽  
Isotope Effects ◽  
Activation Parameters ◽  
Second Order ◽  
Order Rate ◽  
Elimination Reactions

The second-order rate constants have been determined for the β-elimination reactions of 2,2-di-(p-nitrophenyl)-1,1,1-trifluoroethane, 2,2-di-(p-nitrophenyl)-1-fluoroethane, and their β-deuterated analogues with sodium methoxide in methanol. The primary isotope effects and activation parameters for these reactions are reported. It is suggested that the trifluoro-compound reacts via the pre-equilibrium carbanion mechanism (ElcB)R and that the monofluoro compound follows the E2 mechanism via a carbanion-like transition state.

The reinvestigation of the kinetics of the reactions of fluorodi(4-nitrophenyl)ethanes with sodium methoxide in methanol

1982 ◽  
Vol 60 (13) ◽  
pp. 1696-1701 ◽  
Author(s):  
Kenneth T. Leffek ◽  
Grzegorz Schroeder
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Sodium Methoxide ◽  
Isotope Effects ◽  
Activation Parameters ◽  
Elimination Reaction ◽  
Methoxide Ion ◽  
Dimerization Reaction ◽  
Multistep Reaction ◽  
Kinetics Of

The procedure previously described for the preparation of 1-fluoro-2,2,-di(4-nitrophenyl)ethane actually yields 1,1,2-tri-(4-nitrophenyl)ethane. 1-Fluoro-2,2-di(4-nitrophenyl)ethane has been prepared and rate constants, isotope effects, and activation parameters for the β-elimination reaction with methoxide ion in methanol are reported. These parameters indicate a concerted E2 mechanism, with a fairly symmetrical transition state. The subsequent dimerization reaction of the olefin product to yield 1,1,3,3-tetra(4-nitrophenyl)butene-1 is described.The reaction of 1,1,1-trifluoro-2,2-di(4-nitrophenyl)ethane with methoxide ion in methanol has been reinvestigated and the reaction of the first product 1,1-difluoro-2,2-di(4-nitrophenyl)ethylene with excess methoxide, to give di(4-nitrophenyl)ketene dimethylacetal in a multistep reaction, is reported.

Comparing Isotope Effects and Rates for the Methanolic Sodium Methoxide Reactions of 9-R-Fluorene to Those for p-CF3C6H4CHClR (R = CH2Cl, CH2F and CF3)

2002 ◽  
Vol 67 (10) ◽  
pp. 1505-1516 ◽  
Author(s):  
Heinz F. Koch ◽  
William C. Pomerantz ◽  
Erik L. Ruggles ◽  
Martijn van Laren ◽  
Anne-Marie van Roon
Keyword(s):  
Exchange Reaction ◽  
Sodium Methoxide ◽  
Isotope Effects ◽  
Activation Parameters ◽  
Deuterium Exchange

Kinetic primary isotope effects and activation parameters associated with the methanolic sodium methoxide-promoted dehydrohalogenation reactions of 9-(chloromethyl)fluorene and 9-(fluoromethyl)fluorene are reported and compared to for p-CF3C6H4CHClCH2Cl and p-CF3C6H4CHClCH2F. The element effect, kHCl/kHF = 4 at 25 °C, for the fluorenyl compounds is only a tenth of the value, kHCl/kHF = 54, obtained for the benzylic compounds. Also reported are the activation parameters for the methanolic sodium methoxide reactions of 9-(trifluoro)methylfluorene for deuterium exchange and dehydrofluorination, and are compared to those for p-CF3C6H4CHClCF3. In both cases the exchange reaction is faster than the elimination; however, in the fluorenyl system there is a large difference between the entropies of activation for exchange, ∆S≠ = -14 eu, and elimination, ∆S≠ = +10 eu; however, the ∆S≠ of 12-13 eu are the same for the benzylic systems. The eliminations for 9-(chloromethyl)fluorene and 9-(fluoromethyl)fluorene are 80 to 1,000 times faster than those for p-CF3C6H4CHClCH2X. The reactions of 9-(trifluoromethyl)fluorene are favored over p-CF3C6H4CHClCF3 by 200,000 for the dehydrofluorination and 1,000 for the exchange at 25 °C; however, due to the large differences in activation entropies, the exchange reaction is favored by 107 at -50 °C.

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