943-39-5Relevant academic research and scientific papers
Solvation Accounts for the Counterintuitive Nucleophilicity Ordering of Peroxide Anions
Mayer, Robert J.,Tokuyasu, Takahiro,Mayer, Peter,Gomar, Jér?me,Sabelle, Stéphane,Mennucci, Benedetta,Mayr, Herbert,Ofial, Armin R.
supporting information, p. 13279 - 13282 (2017/10/17)
The nucleophilic reactivities (N, sN) of peroxide anions (generated from aromatic and aliphatic peroxy acids or alkyl hydroperoxides) were investigated by following the kinetics of their reactions with a series of benzhydrylium ions (Ar2CH+) in alkaline aqueous solutions at 20 °C. The second-order rate constants revealed that deprotonated peroxy acids (RCO3?), although they are the considerably weaker Br?nsted bases, react much faster than anions of aliphatic hydroperoxides (ROO?). Substitution of the rate constants of their reactions with benzhydrylium ions into the linear free energy relationship lg k=sN(N+E) furnished nucleophilicity parameters (N, sN) of peroxide anions, which were successfully applied to predict the rates of Weitz–Scheffer epoxidations. DFT calculations with inclusion of solvent effects by means of the Integral Equation Formalism version of the Polarizable Continuum Model were performed to rationalize the observed reactivities.
Highly Energetic, Low Sensitivity Aromatic Peroxy Acids
Gamage, Nipuni-Dhanesha H.,Stiasny, Benedikt,Stierstorfer, J?rg,Martin, Philip D.,Klap?tke, Thomas M.,Winter, Charles H.
supporting information, p. 2582 - 2585 (2016/02/26)
The synthesis, structure, and energetic materials properties of a series of aromatic peroxy acid compounds are described. Benzene-1,3,5-tris(carboperoxoic) acid is a highly sensitive primary energetic material, with impact and friction sensitivities similar to those of triacetone triperoxide. By contrast, benzene-1,4-bis(carboperoxoic) acid, 4-nitrobenzoperoxoic acid, and 3,5-dinitrobenzoperoxoic acid are much less sensitive, with impact and friction sensitivities close to those of the secondary energetic material 2,4,6-trinitrotoluene. Additionally, the calculated detonation velocities of 3,5-dinitrobenzoperoxoic acid and 2,4,6-trinitrobenzoperoxoic acid exceed that of 2,4,6-trinitrotoluene. The solid-state structure of 3,5-dinitrobenzoperoxoic acid contains intermolecular O-H?O hydrogen bonds and numerous N?O, C?O, and O?O close contacts. These attractive lattice interactions may account for the less sensitive nature of 3,5-dinitrobenzoperoxoic acid.
The loss of carbon dioxide from activated perbenzoate anions in the gas phase: Unimolecular rearrangement via epoxidation of the benzene ring
Harman, David G.,Ramachandran, Aravind,Gracanin, Michelle,Blanksby, Stephen J.
, p. 7996 - 8005 (2007/10/03)
The unimolecular reactivities of a range of perbenzoate anions (X-C 6H5CO3-), including the perbenzoate anion itself (X = H), nitroperbenzoates (X = para-, meta-, orrtho-NO 2), and methoxyperbenzoates (X = para-, meta-OCH3) were investigated in the gas phase by electrospray ionization tandem mass spectrometry. The collision-induced dissociation mass spectra of these compounds reveal product ions consistent with a major loss of carbon dioxide requiring unimolecular rearrangement of the perbenzoate anion prior to fragmentation. Isotopic labeling of the perbenzoate anion supports rearrangement via an initial nucleophilic aromatic substitution at the ortho carbon of the benzene ring, while data from substituted perbenzoates indicate that nucleophilic attack at the ipso carbon can be induced in the presence of electron-withdrawing moieties at the ortho and para positions. Electronic structure calculations carried out at the B3LYP/6-311++G(d,p) level of theory reveal two competing reaction pathways for decarboxylation of perbenzoate anions via initial nucleophilic substitution at the ortho and ipso positions, respectively. Somewhat surprisingly, however, the computational data indicate that the reaction proceeds in both instances via epoxidation of the benzene ring with decarboxylation resulting-at least initially-in the formation of oxepin or benzene oxide anions rather than the energetically favored phenoxide anion. As such, this novel rearrangement of perbenzoate anions provides an intriguing new pathway for epoxidation of the usually inert benzene ring.
Predominant role of basicity of leaving group in α-effect for nucleophilic ester cleavage
Nomura, Yasuo,Kubozono, Takayasu,Hidaka, Makoto,Horibe, Mineko,Mizushima, Naoki,Yamamoto, Nobuyuki,Takahashi, Toshio,Komiyama, Makoto
, p. 26 - 37 (2007/10/03)
It has been found that α-effects in nucleophilic reactions, unexpectedly large nucleophilicity due to adjacent unpaired electrons, are strongly dependent on the structure of substrate. The nucleophilic cleavages of 4-nitrobenzoate esters and 4-methylbenzo
PHASE TRANSFER CATALYSED PEROXIDATION OF CARBOXYLIC ACIDS WITH POTASSIUM PERSULFATE
Pande, C. S.,Jain, Neena
, p. 2123 - 2128 (2007/10/02)
Aqueous solution of potassium persulfate converts water-insoluble carboxylic acids in ether (or dichloromethane), to peracids in a yield of 80-90percent under the catalytic influence of benzyltriethylammonium chloride (BTEAC) or polyethyleneglycol (PEG-400).The reaction is further catalyzed kinetically in presence of a sulfonated polymer.
Mechanistic and Preparative Studies on the Regio- and Stereoselective Paraffin Hydroxylation with Peracids
Schneider, Hans-Joerg,Mueller, Walter
, p. 4609 - 4615 (2007/10/02)
Reactions of more than 20 hydrocarbons with p-nitro- or, e.g., 3,5-dinitroperbenzoic acid in chloroform show regioselectivities of Rst = 90 (relative rates of attack at tertiary and secondary C-H bonds, after statistical correction) to 500 and configurational retention, if applicable, of typically 97-99.7percent.Radical side reactions are recognized by concomitant formation of, e.g., nitrobenzene and are responsible for a decrease in regio- and stereoselectivity.Steric effects are observed in attack at axial tertiary C-H bonds and at bridgehead positions.Electronegative and hydrogen-bonding substituents in the alkane diminish, and alkyl groups enhance the rates; the observed Taft ρ* value of -2.2 indicates substantial positive charge accumulation in the transition state in agreement with the high regioselectivity.A Hammett reaction constant of +0.63 is obtained from substituted perbenzoic acids; activation parameters of ΔH* = 15-19 kcal mol-1 and ΔS* = -22 to -29 eu with three alkanes of different flexibility and an isotope effect of kH/kD = 2.2 with methylcyclohexane are measured.Aromatic rings are usually not attacked but lead to deactivation of the peracid even at remote alkane C-H positions; similar deactivation is found in hydrogen-bonding solvents.Androstanes yield preferentially 9α- and 5α-hydroxy products, if, e.g., a 17β-acetoxy substituent is used to steer the reaction.Diols usually are only observed as a result of a proximity effect of a peracid associated at the first formed hydroxy group.The results point to relatively late and oxenoid transition states with substantial charge separation in the substrate.Attempts to achieve selective oxidations using macrocyclic azacyclophanes with attached carboxylic functions were not successful, although the host compounds showed selective complexation of hydrocarbons.
