- Preparation method of 3,5-dinitrobenzoic acid
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The invention discloses a preparation method of 3,5-dinitrobenzoic acid. The preparation method comprises the following steps: putting m-dinitrobenzene, a DMF solvent and a metal modified mesoporous material supported guanidine salt ionic liquid into a stainless steel high-pressure reaction kettle, introducing carbon dioxide, increasing the pressure of the carbon dioxide at 80-130 DEG C, keeping the pressure at a specified pressure, carrying out stirring and reacting for 4-20 hours to obtain 3,5-dinitrobenzoic acid, performing filtering to separate an organic phase and a catalyst phase of a product, subjecting a filtrate to distillation, and recrystallizing a crude product with ethanol to obtain a target product. According to the invention, a metal modified mesoporous material supported guanidine salt ionic liquid has good catalytic activity in a carboxylation reaction, a reaction process is high in atom economy, the process of reaction is green, no waste acid is generated, a catalyst can be conveniently recycled, and the preparation method is a novel green and environment-friendly preparation method.
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Paragraph 0037-0048
(2021/11/10)
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- As neuroprotective agents of pharmaceutical compounds
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The invention discloses a medicinal compound as a neuroprotective agent. The medicinal compound is a neuronal nitric oxide synthase-postsynaptic density protein 95 (nNOS-PSD95) decoupling agent. The medicinal compound is a benzene ring derivative shown in the general formula (I) or its pharmaceutically acceptable salt. The invention further discloses a preparation method of the medicinal compound and a use of the medicinal compound in prevention and treatment on neuronal damage influence-caused diseases.
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Paragraph 0123; 0124; 0125; 0126
(2019/06/26)
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- Electrofugalities of 1,3-diarylallyl cations
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Heterolysis rate constants k1 of differently substituted 1,3-diarylallyl halides and carboxylates have been determined in various solvents. The linear free energy relationship log k1 = s f(Nf + Ef) was found to predict the heterolysis rates (log k1) of 1,3-diarylallyl derivatives with a standard deviation of 0.26, corresponding to a factor of 1.82 in k1, and maximum deviation in k1 of a factor of 5. Some systematic deviations are evident, however. Thus, 1,3-diarylallyl carboxylates always react faster and 1,3-diarylallyl chlorides always react more slowly than calculated by the quoted correlation equation when both types of leaving groups were used to determine the electrofugality parameters Ef. As 1,3-diarylalyl cations are generated faster in solvolysis reactions and also react faster with nucleophiles than benzhydrylium ions of similar thermodynamic stabilities, i.e., Lewis acidities, one can conclude that the reactions involving 1,3-diarylallyl cations proceed with lower intrinsic barriers than those involving benzhydrylium ions. The electrofugality parameters Ef of 1,3-diarylallylium ions determined in this work were combined with the electrophilicity parameters E of the corresponding cations as well as with the results on ion pair dynamics reported in preceding papers for generating the full mechanistic spectrum of 1,3-diarylallyl solvolyses.
- Troshin, Konstantin,Mayr, Herbert
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p. 2649 - 2660
(2013/05/08)
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- Kinetic and safety characterization of the nitration process of methyl benzoate in mixed acid
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The nitration of methyl benzoate is studied from a chemical and a kinetic point of view. The reaction network through which the system could evolve following the loss of thermal control or the uncorrect feed of the reagents is completely characterized. The data collected during the present investigation indicate that runaway phenomena can occur during the nitration of the substrate due to the development of side reactions. Isothermal experiments are thus carried out to estimate the unknown kinetic parameters through the adoption of a mathematical model able to predict the system behaviour upon variation of process parameters. The dependence of the acidity function H on the operating conditions is assessed. The proposed model and the estimated parameters are validated through the use of the results collected in a set of experimental runs performed at significantly different operating conditions from those adopted to identify them.
- Di Somma, Ilaria,Marotta, Raffaele,Andreozzi, Roberto,Caprio, Vincenzo
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p. 2001 - 2007
(2013/02/25)
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- Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
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Nucleofugalities of pentafluorobenzoate (PFB) and 2,4,6-trifluorobenzoate (TFB) leaving groups have been derived from the solvolysis rate constants of X,Y-substituted benzhydryl PFBs and TFBs measured in a series of aqueous solvents, by applying the LFER equation: log k = sf(Ef + Nf). The heterolysis rate constants of dianisylmethyl PFB and TFB, and those determined for 10 more dianisylmethyl benzoates in aqueous ethanol, constitute a set of reference benzoates whose experimental ΔG ? have been correlated with the ΔH? (calculated by PCM quantum-chemical method) of the model epoxy ring formation. Because of the excellent correlation (r = 0.997), the method for calculating the nucleofugalities of substituted benzoate LGs have been established, ultimately providing a method for determination of the SN1 reactivity for any benzoate in a given solvent. Using the ΔG? vs ΔH? correlation, and taking sf based on similarity, the nucleofugality parameters for about 70 benzoates have been determined in 90%, 80%, and 70% aqueous ethanol. The calculated intrinsic barriers for substituted benzoate leaving groups show that substrates producing more stabilized LGs proceed over lower intrinsic barriers. Substituents on the phenyl ring affect the solvolysis rate of benzhydryl benzoates by both field and inductive effects.
- Matic, Mirela,Denegri, Bernard,Kronja, Olga
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supporting information
p. 8986 - 8998,13
(2012/12/12)
-
- PROCESS FOR PREPARING SUBSTITUTED AROMATIC CARBOXYLIC ACIDS
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A process for preparing an aromatic carboxylic acid having a heteroatom containing substituent is provided that includes reaction in a vessel of an aromatic precursor having an aromatic core with at least one heteroatom containing substituent and at least one hydrogen extending from the core, with a haloacetonitrile under reaction conditions to form an aromatic acetonitrile with an acetonitrile moiety. The aromatic acetonitrile is exposed to an oxidizing agent under conditions to convert the acetonitrile moiety to a carboxylic acid group to prepare the aromatic carboxylic acid having the heteroatom containing substituent.
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Page/Page column 3
(2010/09/17)
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- Lithium chloride-assisted selective hydrolysis of methyl esters under microwave irradiation
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A rapid and mild method for the selective hydrolysis of methyl ester in lithium chloride-N,N-dimethylformamide (LiCl-DMF) system under microwave irradiation has been developed. The effects of substituent, metal salt, and solvent on the reactivity and selectivity of the hydrolysis reaction have been investigated. Microwave irradiation significantly improves the reaction yield within a short time in an LiCl-DMF system. Moreover, the chiral-carbon of methyl esters retained its configuration during the reaction. Finally, the catalytic mechanism of hydrolysis by LiCl salt has also been proposed.
- Wu, Xiao-Ai,Ying, Ping,Liu, Jun-Yang,Shen, Heng-Shui,Chen, Yue,He, Ling
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experimental part
p. 3459 - 3470
(2009/12/03)
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- Effect of the leaving group solvation on solvolytic behavior of benzhydryl derivatives
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An effect of the leaving group (LG) solvation on reactivity of benzhydryl derivatives in SN1 reactions has been investigated by using X, Y-substituted benzhydryl phenyl carbonates, methyl carbonates, 3, 5-dinitrobenzoates (DNB), and the corresponding benzhydryl chlorides as reference compounds. Reaction constants (sf) derived from LFER equation log k (25°C)=sf (Nf+Ef) indicate that s f parameters of carbonates and DNBs decrease as the fraction of the water in a given solvent/water mixture increases, while those of chlorides remain unchanged. This phenomenon is due to less important solvation and less charge separation in the TS. Effects of the solvents on the reaction rates were analyzed by Grunwald-Winstein correlations using various solvent-ionizing power scales. The m values obtained for carbonates and DNBs are considerably smaller than the m values for chlorides. Also, the solvolysis rate constants of substrates that have stronger electrofuges are less influenced by solvent (lower m) than those with weaker electrofuges. Values of m parameters obtained for a given substrate in a given binary solvent system correlate well with the electrofugality of the generated benzhydrylium ion. Abscissa at which m=0 represents the extrapolated critical electrofugality Ecrit f of the substrates whose solvolysis rates should not depend on the water fraction in the aqueous/organic solvent mixtures. Similar values for the critical electrofugality have also been obtained from extrapolated logk versus Ef plots. Copyright
- Denegri, Bernard,Kronjaa, Olga
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experimental part
p. 495 - 503
(2010/04/30)
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- Bromination of deactivated aromatics: A simple and efficient method
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(Chemical Equation Presented) Highly deactivated aromatic compounds were smoothly monobrominated by treatment with N-bromosuccinimide (NBS) in concentrated H2SO4 medium affording the corresponding bromo derivatives in good yields. Mild reaction conditions and simple workup provides a practical and commercially viable route for the synthesis of bromo compounds of deactivated aromatics.
- Rajesh,Somasundaram,Saiganesh,Balasubramanian
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p. 5867 - 5869
(2008/02/09)
-
- 3-Oxy-5-phenyl-1H-1,2,3-triazole-4-carboxylic acid. Synthesis, structure, and properties
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The structure of 3-oxy-5-phenyl-1H-1,2,3-triazole-4-carboxylic acid was determined both experimentally (by the X-ray diffraction method) and by quantum-chemical calculations. Alkylation of 3-oxy-5-phenyl-1H-1,2,3-triazole-4- carboxylic acid (as crystal hydrate) with methyl iodide, depending on the reactant ratio, gives 1-methoxy-4-phenyl-1H-1,2,3-triazole-5-carboxylic acid and methyl 1-methoxy-4-phenyl-1H-1,2,3-triazole-5-carboxylate. Nitration of the title compound under mild conditions occurs at the 5-phenyl group with formation of meta-nitro derivative, while under more severe conditions 3,5-dinitrobenzoic acid is obtained. 3-Oxy-5-phenyl-1H-1,2,3-triazole-4-carboxylic acid was also converted into the corresponding acid chloride and substituted amide.
- Shtabova,Shaposhnikov,Mel'nikova,Tselinskii,Nather,Traulsen,Friedrichsen
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p. 591 - 598
(2007/10/03)
-
- Facile Hydrolysis of Esters with KOH-Methanol at Ambient Temperature
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A simple, rapid, and efficient method is reported for the hydrolysis of a variety of mono-and diesters of aromatic, aliphatic, fatty, and heterocyclic acids with potassium hydroxide in methanol at ambient temperature (~35°C).
- Khurana, Jitender M.,Chauhan, Sushma,Bansal, Geeti
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- Facile and selective deprotection of allyl esters catalyzed by H-β zeolite
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Carboxylic acids are regenerated from their corresponding allyl or cinnamyl esters by H-β zeolite under environmentally safe, heterogeneous reaction conditions in excellent yields.
- Pandey, Rajesh K.,Kadam, Vijay S.,Upadhyay, Rajesh K.,Dongare, Mohan K.,Kumar, Pradeep
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p. 3017 - 3024
(2007/10/03)
-
- Reinterpretation of curved hammett plots in reaction of nucleophiles with aryl benzoates: Change in rate-determining step or mechanism versus ground-state stabilization
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A kinetic study is reported for the reaction of the anionic nucleophiles OH-, CN-, and N3- with aryl benzoates containing substituents on the benzoyl as well as the aryloxy moiety, in 80 mol % H2O-20 mol % dimethyl sulfoxide at 25.0 °C. Hammett log k vs σ plots for these systems are consistently nonlinear. However, a possible traditional explanation in terms of a mechanism involving a tetrahedral intermediate with curvature resulting from a change in rate-determining step is considered but rejected. The proposed explanation involves ground-state stabilization through resonance interaction between the benzoyl substituent and the electrophilic carbonyl center in the two-stage mechanism. Accordingly, the data are nicely accommodated on the basis of the Yukawa-Tsuno equation, which gives linear plots for all three nuceophiles. Literature reports of the mechanism of acyl transfer processes are reconsidered in this light.
- Um, Ik-Hwan,Han, Hyun-Joo,Ahn, Jung-Ae,Kang, Swan,Buncel, Erwin
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p. 8475 - 8480
(2007/10/03)
-
- Deprotection of benzylic esters catalysed by anhydrous ferric chloride and rhenium carbonyl compounds
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Anhydrous ferric chloride and [Re(CO)4Br]2 are shown to be useful reagents for the catalytic deprotection of benzylic esters. A suitable protecting group is p-MeC6H4CH2 with a working temperature of 5
- Davies, Timothy J.,Jones, Ray V.H.,Lindsell, W.Edward,Miln, Colin,Preston, Peter N.
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p. 487 - 488
(2007/10/03)
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- Evidence of a stepwise acyl-transfer reaction mechanism: Nonlinear hammett plots for reactions of p-nitrophenyl substituted benzoates with hydroxide and p-chlorophenoxide
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The Hammett plots obtained for the title-reactions exhibit a break, i.e. ρ acyl values decrease from 2.21 ~ 2.44 to 1.45 ~ 1.52 as the acyl substituent becomes a strong electron withdrawing group (σ > 0.6). Such a break in the Hammett plots is suggestive of a change in the reaction mechanism and strong evidence of a stepwise mechanism for the acyl-transfer reaction.
- Um, Ik-Hwan,Chung, Eun-Kyung,Kwon, Dong-Sook
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p. 4787 - 4790
(2007/10/03)
-
- Reactivity of Activated Methylene Group in Nitro Compounds. III. Formation of 2,4,6-Trinitrobenzonitrile in the Reaction of 2,4,6-Trinitrotoluene with Carboxylic Acid Chlorides and Anhydrides
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With the reactions of 2,4,6-trinitrotoluene with carboxylic acid chlorides and anhydrides in the presence of pyridine as examples we showed for the first time that nitrogen atom of a nitro group can be involved in formation of a cyano group.
- Zbarskii, V. L.,Yudin, N. V.,Ivchenko, A. N.,Derevitskaya, A. G.
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p. 1075 - 1076
(2007/10/03)
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- DESTRUCTIVE NITRATION OF ALIPHATIC γ,γ-DINITRO KETONES AND ALDEHYDES. SYNTHESIS OF HALOGENOPENTANITROETHANES AND 1,1,1,2,2-PENTANITROPROPANE
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The nitration of 2,2-dinitro-2-R-5-pentanones ( R = H, Cl, Br ) with a mixture of nitric and sulfuric acids leads to R'-pentanitroethanes ( R' = NO2, Cl, Br ). 1,1,1,2,2-Pentanitropropane was obtained similarly with 56-58percent yields during the nitration of 2,2-dinitro-5-hexanone, 2,2-dinitro-5-phenyl-5-pentanone, and 4,4-dinitropentanal.
- Tselinskii, I. V.,Shokhor, I. N.,Bagal, L. I.
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p. 1039 - 1041
(2007/10/02)
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- KINETICS AND MECHANISM OF THE IMIDAZOLE-CATALYSED HYDROLYSIS OF SUBSTITUTED N-BENZOYLIMIDAZOLES
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Imidazole (Imz)-catalysed hydrolysis of benzoate esters proceeds via the intermediate formation of N-benzoylimidazoles.This paper considers the second step of this reaction, viz., Imz-catalysed hydrolysis of N-(4-X-benzoyl)imidazoles, X = CH3, H, Cl, CN and NO2, and N-(disubstituted benzoyl)imidazoles, 2-chloro-4-nitro, 2,4-dinitro and 3,5-dinitro, in water-acetonitrile mixtures (10percent or 14percent, v/v, in organic solvent).On the basis of catalytic rate constants and the kinetic solvent isotope effect, it is shown that catalysis by Imz is of the general-base type.Unexpectedly, the hydrolysis of N-(2,4-dinitrobenzoyl)imidazole was found to be slower than that of N-(4-nitrobenzoyl)imidazole.It is shown that this reactivity order is due to a combination of a steric effect and stabilization of the reactant state due to a donor-acceptor interaction between the Imz moiety and the 2,4-dinitrophenyl ring.
- Seoud, Omar A. El,Menegheli, Paulo,Pires, Paulo A. R.,Kiyan, Nilo Z.
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p. 431 - 436
(2007/10/02)
-
- Photochemical Nitration by Tetranitromethane. XV. Formation of Adducts and their Secondary Products in the Photochemical Reaction between Benzene and Tetranitromethane
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Photolysis of benzene/tetranitromethane in dichloromethane or acetonitrile with light of λ>435 nm gives four main product categories, namely, in dichloromethane at +20 deg C (relative yield, products): adducts 1 of hydroxy/trinitromethyl type (total 54percent, see below), nitro substitution products (total 8percent, nitrobenzene, 1,3-dinitrobenzene and 1,3,5-trinitrobenzene), trinitromethyl substitution products (26percent, trinitromethylbenzene, 1-nitro-4-trinitromethylbenzene, 1,3-dinitro-5-trinitromethylbenzene) and phenols (total 12percent, 2,4- and 2,6-dinitrophenol, 2,4,6-trinitrophenol). In acetonitrile at +20 deg C the same product groups comprised 15, 24, 39 and 18percent, respectively, and, in addition, a low yield (1.7percent) of what is formally a cycloaddition product between 4-nitrobenzonitrile N-oxide and acetonitrile, 5-methyl-3-(4-nitrophenyl)-1,2,4-oxadiazole 2. The structure of 2 was determined by single crystal X-ray analysis. The main adducts were assigned the structures of a cis/trans pair of 1-hydroxy-4-trinitromethylcyclohexa-2,5-diene (NMR). Their formation in both dichloromethane and acetonitrile shows that adduct formation from photolysis of tetranitromethane/aromatics is not only confined to polycyclic aromatics but can occur with a maximally resonance-stabilized system, like benzene itself. The high complexity of the product mixture can be explained partly by elimination reactions of adducts, combined with further thermal and photochemical transformations.
- Eberson, Lennart,Calvert, Jane L.,Hartshorn, Michael P.,Robinson, Ward T.
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p. 347 - 355
(2007/10/02)
-
- Electrophilic Aromatic Substitution. Part 37. Products of Aromatic Nitrations of some Chloronitrobenzenes and Substituted Benzoic Acids in Solutions of Dinitrogen Pentaoxide and of Nitronium Salts in Nitric Acid
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Yields of aromatic products of nitration in nitric acid solutions containing dinitrogen pentaoxide or nitronium salt have been determined.Evidence for the intrusion of a mechanism other than the normal nitronium ion one comes from comparison of products in the two media and from the observation of 15N NMR CIDPN effects.The additional mechanism operative with some substrates in concentrated solutions of dinitrogen pentaoxide is postulated to be one in which reversible addition of the NO3 radical is followed by combination with NO2.Dienes produced in this way can give aromatic nitroproducts by elimination of nitric acid.Nitrodecarboxylation of substituted benzoic acids occurs by a radical process.
- Moodie, Roy B.,Sanderson, Andrew J.,Willmer, Richard
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p. 645 - 650
(2007/10/02)
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- Single-electron transfer in deacylation of ethyl dinitrobenzoates
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Reactions of OH- with ethyl 2,4- and 3,5-dinitrobenzoate (2,4-DNB and 3,5-DNB) in DMSO/H2O 1:1 (v/v) involve single-electron transfer from OH- into the antibonding orbital of the substrate to form a charge transfer complex of OH and the radical anion. This complex collapses into a tetrahedral intermediate that gives products. Nonproductive Meisenheimer complexes form and gradually disappear. The rate and equilibrium constants of the various reaction steps can be calculated by using relaxation theory. The charge transfer complexes lead to hydrogen exchange of both substrates and products in DMSO-d6/D2O/OD- and 1H signals of the esters broaden during reaction. Exchange of the carboxylate ions is slow. The 2-and 4-Mcisenheimer complexes of OD- and 3,5-DNB are detected by 1H NMR R spectroscopy. Semiempirical MO calculations with AM1 parameters predict that formation of charge transfer and Meisenheimer complexes, and of the tetrahedral intermediate, is enthalpically favored in the absence of solvent interactions and hydration of OH- is a significant barrier to reaction.
- Bacaloglu, Radu,Blaskó, Andrei,Bunton, Clifford A.,Ortega, Francisco
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p. 9336 - 9344
(2007/10/02)
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- A Novel Dissociative Mechanism in Acyl Group Transfer from Aryl 4-Hydroxybenzoate in Aqueous Solvents.
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The hydrolysis of ary 4-hydroxybenzoates esters exibits the kinetic rate law kobsd=(ka+kb->/(1++>/Ka) where kb is the second-order rate constant for hydroxide ion attack on the ionized ester and Ka is the ionization constant.The apparent second-order rate constant for the hydrolysis of the 2,4-dinitrophenyl ester (kaKa/Kw) is some 340-fold larger than that determined from the Hammett correlation for the alkaline hydrolysis of substituted 2,4-dinitrophenyl benzoates known to possess a BAc2 mechanism.A slightly positive entropy of activation for ka and aniline trapping experiments for the 2,4-dinitrophenyl ester are consistent with a mechanism where a p-oxo ketene intermediate takes the reaction flux. Correlation of kaKa/Kw with the pK of the leaving phenol fits the equation kaKa/Kw-10(-1.33pK+9.57)+10(-0.35pK+3.51) which favors the BAc2 mechanism for poor leaving groups and the E1cB pathway for good leaving groups.There is no reason to postulate a borderline concerted displacement process in this case.
- Cevasco, Georgio,Guanti, Giuseppe,Hopkins, Andrew R.,Thea, Sergio,Williams, Andrew
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p. 479 - 484
(2007/10/02)
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- Nitrosation of the N-Alkyl-O-acylhydroxylamines. A New Deamination Method.
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The nitrosation of N-alkyl-O-acylhydroxylamines leads to immediate decomposition at dry ice temperatures; the corresponding ester and nitrous oxide are formed.An 18O study has shown that the nitroso-O-acylhydroxylamines fragment directly rather than undergo a rearrangement reaction (as observed with the nitrosoamides).The product yields are respectable, especially at low tempreatures, and the method has promise for the generation of high energy carbonium ions.
- White, Emil H.,Ribi, Max,Cho, Lee K.,Egger, Notker,Dzadzic, Petar M.,Todd, Michael J.
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p. 4866 - 4871
(2007/10/02)
-
- One-electron Oxidation of Closed-shell Molecules. Part 3. Oxidative Cleavage of 1,2,2,2-Tetrakis-(p-methoxyphenyl)ethanone with Dibenzoyl and Bis(3,5-dinitrobenzoyl) Peroxides: Mechanistic Changeover of the Peroxide Function from Radical to Molecular Oxidation
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1,2,2,2-Tetrakis-(p-methoxyphenyl)ethanone (anispinacolone) (1) is cleaved by dibenzoyl peroxide (2) or bis-(3,5-dinitrobenzoyl) peroxide (3), affording tris-(p-methoxyphenyl)methyl benzoate (or 3,5-dinitrobenzoate) and benzoic (or 3,5-dinitrobenzoic) p-methoxybenzoic anhydride as the principal cleavage products. 13C N.m.r.CIDNP studies by use of labelled anispinacolone (An3*C-*COAn ; *C 90percent 13C) indicated that p-methoxybenzoyl radical is formed, presumably by way of the radical cation +. which is produced by a single-electron transfer (s.e.t.) mechanism.The formation of the p-methoxybenzoyl radical was also indicated by spin-trapping experiments.The decomposition rates of (2) at 50.0 deg C are unaltered on addition of (1) in nonpolar solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, and benzene, whereas those of (3) are markedly accelerated.The cleavage of (1) by (2) is supressed by added 3,4-dichlorostyrene by a factor of 6.7, whereas that of (1) by (3) is almost unaffected.These results suggest that in the case of dibenzoyl peroxide (2) the thermally produced benzoyloxyl radical works as a one-electron acceptor (or oxidant) upon (1), whereas when bis-(3,5-dinitrobenzoyl) peroxide (3) is used the peroxide molecule oxidizes (1), probably by way of an s.e.t. mechanism even in such nonpolar solvents.On the other hand, in polar solvents such as (CF3)2CHOH, teramethylene sulphone, and acetonitrile the decomposition of (2) is accelerated by added anispinacolone, suggesting that the intermolecular s.e.t. reaction is partially involved in such polar solvents.Consequently, the oxidative cleavage of anispinacolone (1) by diaroyl peroxides provides the first example of dichotomy in the s.e.t. reaction of diaroyl peroxides, which can be considered a counterpart of the SN1-SN2 dichotomy in nucleophilic substitution, as far as the molecularity of the peroxide is concerned.
- Takeuchi, Ken'ichi,Murai, Osamu,Matsui, Shin,Inoue, Takeshi,Kitagawa, Toshikazu,Okamoto, Kunio
-
p. 1301 - 1310
(2007/10/02)
-
- Substituent Effect Behavior in the Antiaromatic Inden-1-yl Cation System
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Studies of the rate-accelerating effects in solvolysis produced by 5-methyl and 5-methoxy substituents on the benzene ring and a 3-methyl substituent on the double bond of the inden-1-yl 3,5-dinitrobenzolate system have been carried out.In both 80percent aqueous acetone and in 2,2,2-trifluoroethanol, the rate accelerations observed in the inden-1-yl system were approximately the same as those found in model cyclopenten-3-yl and indan-1-yl systems.From these results, it is concluded that delocalization of charge into both the benzene ring and double bond of the 8?-electron inden-1-yl carbocation is taking place and is apparently undiminished by antiaromatic effects.
- Friedrich, Edwin C.,Tam, Teresa M.
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p. 315 - 319
(2007/10/02)
-
- Synthesis of Unlabelled and Carboxyl-Labelled 3-Amino-5-hydroxybenzoic Acid
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Efficient syntheses are reported of the natural amino acid 3-amino-5-hydroxybenzoic acid in unlabelled and carboxyl-labelled forms from 3,5-dinitrobenzoic acid and 3,5-dinitroanisole, respectively.
- Herlt, Anthony J.,Kibby, Jeffrey J.,Rickards, Rodney W.
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p. 1319 - 1324
(2007/10/02)
-
- Process for the production of nitro derivatives of aromatic compounds
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Nitroderivates of aromatic compounds which are difficult to nitrate, can readily be obtained by nitration providing that the aromatic compound is treated with nitric acid or another nitrating agent in the presence of aliphatic or cycloaliphatic hydrocarbons monosubstituted or polysubstituted by halogen, the nitro group or an alkyl sulphonyl group, and the nitro derivative formed subsequently isolated.
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