93-59-4

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Potentiometric or combined potentiometric and spectrophotometric or kinetic techniques have been used to determine stability constants for complexes between α-cyclodextrin and 20 of the title compounds. Linear free energy relationships indicate that 4-substituted benzoic acids, perbenzoic acids and perbenzoates have predominantly the same orientation within the cyclodextrin cavity, with the carboxylic acid, percarboxylic acid and percarboxylate groups located at the narrow (primary hydroxy) end of the cavity. 4-Substituted benzoates orientate in the opposite way with the carboxylate group located at the wide end of the cavity. Alkyl carboxylic acids, percarboxylic acids and their anions show a linear dependence between log stability constant and the number of carbons. They are likely to bind with the functional group at the narrow end of the cavity, although the carboxylate groups will probably be located outside the cavity because of solvation requirements. 2:1 cyclodextrin-guest complexes are observed for several of the compounds studied.

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The N-hydroxyphthalimide derivative-mediated aerobic oxidation of a selection of aldehydes to the corresponding carboxylic acids in air is described. This reaction proceeds via rearrangement of the Creigee (carboxylic peracid) intermediate and/or by the treatment of H2O and/or sulfides. Optimization of reaction conditions established NHNPI (14) as a mild catalyst for the oxidation reaction in MeCN under an atmosphere of air.

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.

Cyperus scariosus is a potential medicinal herb belonging to the family Cyperaceae. The GC-MS analysis of the oil showed cyprene (18.57 %) as the major terpene present in it. Cyprene was isolated from the non-polar fraction of the oil using hexane as solvent and characterized using TLC and spectral techniques (IR and 1H NMR). Cyprene was derivatized to cyprene epoxide by two methods i.e. using perbenzoic acid and epichlorohydrin. Further, the oil, it's polar fraction (dichloromethane), non-polar fraction (hexane), cyprene and cyprene epoxide were screened for their plant growth regulating property in case of wheat seedlings (HD 2967 and PBW 621). Complete germination was observed above 2.5 μg/mL of all the test fractions in both the cultivars. Moreover, cyprene epoxide was found to be the most effective in enhancing the length of roots and shoots. Seedling vigour index was calculated in order to analyze the enhancement shown by the oil and its various components on the seedlings.

We developed an aerobic photooxidative synthesis of peroxybenzoic acids from toluenes using anthraquinone-2-carboxylic acid (AQN-2-CO2H) as a photocatalyst. We also found a one-pot epoxidation reaction of alkenes using 4-tert-butylperoxybenzoic acid produced in situ by aerobic photooxidative synthesis.

The use of compounds in the treatment of skin disorders is described. In particular, compounds having the general formula (I): are described. A process for preparing such compounds and their cosmetic or dermatological use are also described. The described compounds can act as bactericides. As a result, they can be useful in the treatment of conditions associated with the presence of bacteria, more specifically of P. acnes.

A facile photooxidation of alcohols to obtain carboxylic acids and ketones using easily handled 2-chloroanthraquinone as an organocatalyst under visible light irradiation in an air atmosphere is reported. The reaction conditions are mild, such as an air atmosphere and ambient pressure and temperature. Georg Thieme Verlag Stuttgart New York.

The present invention relates to the use of the compounds of following general formula (I): It also relates to their process of preparation and to their therapeutic application.

We report the catalytic oxidative cleavage of 1,3-diketones to the corresponding carboxylic acids by aerobic photooxidation with iodine under irradiation with a high-pressure mercury lamp. Georg Thieme Verlag Stuttgart. New York.

This work reports the ultraviolet absorption spectrum and the kinetic determinations of the reactions 2C6H5C(O)O2 → products (I) and C6H5C(O)O2 + HO 2 → C6H5C(O)O2H + O2 (IIa), → C6H5C(O)OH + O3 (IIb), → C6H5C(O)O + OH + O2 (IIc). Experiments were performed using a laser photolysis technique coupled with UV-visible absorption detection over the pressure range of 80-120 Torr and the temperature range of 293-357 K. The UV spectrum was determined relative to the known cross section of the ethylperoxy radical C2H5O2 at 250 nm. Kinetic data were obtained by simulating the temporal behavior of the UV absorption at 245-260 nm. At room temperature, the rate constant value of reaction I (cm3 . molecule-1 . s-1) was found to be kI ) (1.5 ± 0.6) × 10-11. The Arrhenius expression for reaction II is (cm3 . molecule-1 . s -1) kII(T) ± (1.10 ± 0.20) × 10 -11 exp(364 ± 200/T). The branching ratios βO3 and βOH, respectively, of reactions IIb and IIc are evaluated at different temperatures; βO3 increases from 0.15 ± 0.05 at room temperature to 0.40 ± 0.05 at 357 K, whereas βOH remains constant at 0.20 ± 0.05. To confirm the mechanism of reaction II, a theoretical study was performed at the B3LYP/6-311++G(2d,pd) level of theory followed by CBS-QB3 energy calculations.

A new and efficient method for the synthesis of lactones involving the application of an oxygen/benzaldehyde system as the oxidant and ionic liquids as solvents is reported. A significant rate enhancement was observed at 90 °C when the oxidation of ketones was carried out in the presence of a free radical initiator. The oxidation of model cyclic ketones, such as cyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2-norbornone, 2-adamantanone and cycloheptanone gave lactones in high yields (84-90%) within relatively short periods of time, with the possibility of effective ionic liquids recycling. Additionally, discussion of the free radical mechanism of this reaction is proposed.

The kinetics of oxidation of Mn(II) with acylperoxyl and alkylperoxyl radicals were determined by laser flash photolysis utilizing a macrocyclic nickel complex as a kinetic probe. Radicals were generated photochemically from the appropriate ketones in the presence of molecular oxygen. In both acidic aqueous solutions and in 95% acetic acid, Mn(II) reacts with acylperoxyl radicals with k = (0.5-1.6) × 106 M-1 s-1 and somewhat more slowly with alkylperoxyl radicals, k = (0.5-5) x 10 5 M-1 s-1. Mn(III) rapidly oxidizes benzyl radicals, k = 2.3 × 108 M-1 s-1 (glacial acetic acid) and 3.7 × 108 M-1 s-1 (95% acetic acid). The value in 3.0 M aqueous perchloric acid is much smaller, 1× 107 M-1 s-1. The decarbonylation of benzoyl radicals in H2O has k = 1.2 × 106 s -1.

(Chemical Equation Presented) We demonstrate in this work by theory and experiment that benzaldehyde hydrotrioxide (PhC(O)OOOH), the intermediate most likely formed in the low-temperature ozonation of benzaldehyde, is too unstable to be detected by NMR (1H, 13C, and 17O) spectroscopy in various organic solvents at temperatures ≥ -80°C and that its previous detection must have been erroneous. Several plausible mechanisms for the formation of this polyoxide were explored by using density functional theory. We found that the formation of the hydrotrioxide involves the facile 1,3-dipolar insertion of ozone into the C-H bond (ΔH? =11.1 kcal/mol) in a strongly exothermic process (ΔHR = -57.0 kcal/mol). The hydrotrioxide then quickly decomposes in a second concerted, exothermic reaction involving an intramolecular H transfer to form benzoic acid and singlet oxygen (O2(1Δg)) (ΔH? = 5.6 kcal/mol), ΔHR = -14.0 kcal/mol). The equilibrium is thus expected to be shifted toward the products; therefore, this intermediate cannot be observed experimentally. Peroxybenzoic acid, still another major reaction product formed in the ozonation reaction, is formed as a result of the surprising instability of the RC(O)O-OOH bond (ΔH R = 23.5 kcal/mol), generating HOO? and benzoyloxyl radicals. Both of these radicals can then initiate the chain autoxidation reaction sequence - the abstraction of a H atom from benzaldehyde to form either a benzoyl radical and HOOH or a benzoyl radical and benzoic acid. Because only very small amounts of HOOH were detected in the decomposition mixtures, the recombination of the benzoyl radical with the HOO? radical (ΔHR = -80.7 kcal/mol) appears to be the major source of peroxybenzoic acid. A theoretical investigation of the mechanistic possibility of the involvement of still another intermediate, a cyclic tetraoxide (tetraoxolane) formed as a primary product in the 1,3-dipolar cycloaddition of ozone to the carbonyl group of the aldehyde, revealed that the tetraoxide is a "real" molecular entity with the five-membered ring adopting an envelope conformation. The tetraoxide is destabilized by 7.0 kcal/mol relative to the reactant complex, and the transition state for its formation is 17.4 kcal/mol above the reactant complex, which, although accessible under the reaction conditions, is not expected to be competitive with the reaction generating the hydrotrioxide.

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.

A process for the faster manufacturing of hydrocarbon, fluorocarbon and chlorocarbon acyl peroxides is disclosed wherein a hydroxide, a peroxide and an acyl halide are reacted under continuous vigorous agitation conditions so as to bring the reaction to substantial completion is less than one minute.

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A polymer-supported persulfonic acid has been prepared and applied for the oxidation of carboxylic acids, ketones, olefins, and disulfide bonds of cystine and cystinyl peptides to their peracids, esters (lactones), epoxides and sulfonic acid derivatives respectively in good yields.The resin also effectively removed the formyl protection from formyl amino acids.Spent polymer was reactivated by simple reactions.

The liquid-phase oxidation of benzaldehyde with oxygen in a solution in o-dichlorobenzene in the presence of benzil leads to the transformation of the latter into benzoic anhydride under the influence of the intermediate perbenzoic acid with a yield close to quantitative on the transformed benzil.For the case of the transformation of benzil in the deoxybenzoin being oxidized as medium it was established that the formation of carboxylic acid anhydrides from the diketones in the ketones being oxidized as medium also involves the action of proxy compounds present in the reaction medium.

Irradiation of benzophenone and 2,2-dimethoxy-2-phenylacetophenone (DMPA) in the presense of some 4-(dialkylamino)azobenzenes (2) causes decomposition of these dyes.The products formed are the N-monoalkyl derivatives (3), the N-acyl derivatives (4), the N-oxides (5), and products arising from cleavage of the Ar-N bond.N-Oxides arise from the reaction of perbenzoic acid, formed in the decomposition of DMPA in aerated solution.The other processes originate from electron transfer to triplet benzophenone or to benzoylperoxy radical (from DMPA), followed by proton transfer and reaction of the α-amino radical with oxygen.The effect of substituents on these reactions is discussed.

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.

The factors which control the reactivity of alkyl free radicals R. in reaction (i) are studied.The reactivity of R. in (i) depends on the key orbital interaction between the SOMO of the radical and the LUMO of the peroxyacid.This interaction involves two contributions: (i) the energy gap SOMO-LUMO and (ii) the overlap SOMO-LUMO.In reaction (i) the main factor is overlap control which depends on spin delocalisation in the radical R..This proves that reaction (i) does not involve electron transfer.The energy gap control, which depends on the nucleophilic character of R., is only observed when the first factor is constant along a series of R..

For elucidation of the relationships associated with the sequence of accumulation of the reaction products and decomposition of the alpha -keto hydroperoxide formed, the authors studied the oxidation of an aromatic ketone, deoxybenzoin. Oxidation of a ketone of this type should yield a secondary alpha -keto hydroperoxide as the primary molecular product. It is shown that destruction of deoxybenzoin in the course of its oxidation in the liquid proceeds through initial formation of the alpha -keto hydroperoxide which decomposes in th reaction media mainly with cleavage of the C-C bond and partially without such cleavage, with formation of benzil and benzoin.

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.

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The benzil- and biacetyl-sensitized photoepoxidation of olefins in the presence of oxygen has been studied.The photolytic loss of diketone is not affected by the presence of olefins; the ratio of epoxide formation to diketone consumption is in the range of 1-3.An (18)O-tracer study shows that the epoxide oxygen derives from molecular oxygen and that the recovered oxygen does not scramble.The photoepoxidation is accompanied by C-C bond cleavage; the ratio of epoxidation to C-C scission is not affected by solvent polarity and only slightly affected by the presence of diazabicyclooctane (Dabco).These results are explained by a mechanism involving the addition of oxygen to triplet diketone to give an acylperoxy radical, which is a key epoxidizing species.

In dimethylformamide (DMF) superoxide ion (O2-) oxygenates compounds with the trichloromethyl group: CCl4, HCCl3, and FCCl3 yield bicarbonate ion; PhCCl3 yields a mixture of PhC(O)OO- and PhC(O)O-; CF3CCl3 and HOCH2CCl3 give their carboxylate anions, RC(O)O-; and p,p'-DDT yields its dechlorinated product, DDE, which in turn reacts with O2- to give (p-ClPh)2C=O.Alkyl trichloromethyl compounds are unreactive within a 10-min reaction time at millimolar concentrations.The relative rates of reaction have been measured by the rotated ring-disc voltammetric method.On the basis of the relationship between the relative reaction rates and the electrophilic character of the substrates, as measured by the peak reduction potentials (Ep), the initial step is believed to be an electron transfer from the nucleophile to the electrophilic trichloromethyl group (a nucleophilic attack on chlorine with a concerted reductive displacement of Cl- and formation of RCCl2OO*).

The oxidation of benzaldehyde is catalyzed by transition metal ions even when these are present in trace concentrations.In complete absence of the ions, the reaction between benzaldehyde and dioxygen would not take place.A study has been made of the oxidation of benzaldehyde in benzene catalyzed by transition metal complexes.The catalytic activity of transition metals is higher when they assume their lower oxidation states.When the reaction is catalyzed by iron (III) bis (2,4-pentanedionato)complex, the first reaction step is the reduction of Fe(III) to Fe(II), the later being the catalyst of the thermal reaction.The mechanism proposed for the catalyzed reaction does not involve free radical formation.

The photoinitiated oxidation of benzaldehyde is catalyzed by traces of transition metal ions.The photocatalytic effects of transition metals are explained in terms of the formation of their unstable oxidation states which act as catalysts of the thermal oxidation.The reaction catalyzed by Fe(II) and Fe(III) ions is discussed in detail.

The photooxidation of benzoylformic acid (1a) in benzene gave peroxybenzoic acid, hydrogen peroxide, and phenyl benzoate.The addition of α-methylstyrene to the oxidation system afforded the epoxide together with acetophenone as a C-C cleaved product, and the ester yield was significantly increased at the expense of the peracid.The photooxidation of 1a was not sensitized by methylene blue or other sensitizers, but was efficiently accelerated by pyridine or other weakly basic solvents such as ethers.Pyridine effectively catalyzed the photoepoxidation as well as the photodecarboxylation of 1a to benzaldehyde.The photoepoxidation gave predominantly trans epoxides, and the relative reactivities of olefins were similar to the photoepoxidation with benzoin (i.e., PhCO3.) and quite different from the peracid epoxidation.Similar results were obtained by other α-keto acids or the corresponding esters.These facts suggest that the photoepoxidation proceeds via radical epoxidation by acylperoxy radical, affording trans epoxide predominantly.Contrary to previous reports, the photooxidation of α-keto acids via an 1O2 reaction was not substantiated.The photodecarboxylation of 1a to afford benzaldehyde was selectively catalyzed by water, and its undissociated form was about tenfold more reactive than the corresponding carboxylate ion.

Benzoin was photooxidized to yield benzaldehyde, peroxybenzoic acid, and hydrogen peroxide.The addition of styrenes to this photooxidation system afforded high yields of epoxides together with some C-C cleaved products.While the C-C cleavage products increased with increasing concentration of olefins, the epoxide yield was constant and nearly quantitative; the stoichiometry at the infinite olefin concentration was such that 1 mol of benzoin produces 1 mol of epoxide and 2 equiv of C-C cleaved product.The effect of olefin concentration is analyzed to show that the C-C cleavage is ascribed to benzoyloxy and α-hydroperoxy radicals, PhCH(OH)OO..The photoepoxidation proceeds by a way of acylperoxy radical, affording predominantly trans-epoxide (e.g., 100percent trans-epoxide from stilbenes and 77percent trans-epoxide from 2-octenes).The relative reactivities of olefins differ significantly from those with molecular peroxyacid; the additivity of methyl substitution does not hold, and aliphatic olefins are less reactive than the corresponding aromatic ones.The relative reactivities of photoepoxidation are examined on the basis of the stability of a resulting adduct radical between the acylperoxy radical and olefin.The peroxy radical is not reactive toward pyridine or sulfoxides.The photoepoxidation with benzoin ethers proceeds similarly except the formation of esters, which is explained by the β-scission or the 1,2-phenyl migration of intermediary α-alkoxy radical.These results are discussed in relation to practical photopolymerizations and to an origin of photoxic substances.

5-Phenethyl oxazolidone compounds having the formula: STR1 wherein R represents a hydrogen or halogen atom or a lower alkoxy group have muscular relaxing, analgetic and antiinflammatory activities.

Tropone derivatives substituted with an amino-derivative of oxalic acid or acetic acid are disclosed. In addition, the tropone nucleus can be optionally further substituted. The foregoing compounds are useful for preventing or treating allergic conditions in a mammal. Methods for the preparation and use of the compounds are disclosed.

5-Benzyl-2-oxazolidone derivatives of the formula: STR1 wherein R1 represents a hydrogen, halogen, lower alkyl, trihalogenomethyl, phenyl, benzyl, hydroxy, lower alkoxy, phenoxy, benzyloxy, acyloxy, allyloxy, alkylcarbonyl, arylcarbonyl or alkylenedioxy group, and R2 represents a hydrogen atom, a lower alkyl, lower alkylcarbonyl, lower-dialkylamino-lower-alkyl, aryl, aralkyl or arylcarbonyl group.