- Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
-
The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
- Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
-
p. 167 - 175
(2021/03/19)
-
- Synthesis and structure-activity relationships of new 2-phenoxybenzamides with antiplasmodial activity
-
The 2-phenoxybenzamide 1 from the Medicines for Malaria Venture Malaria Box Project has shown promising multi-stage activity against different strains of P. falciparum. It was successfully synthesized via a retrosynthetic approach. Subsequently, twenty-one new derivatives were prepared and tested for their in vitro activity against blood stages of the NF54 strain of P. falciparum. Several insights into structure-activity relationships were revealed. The antiplasmodial activity and cytotoxicity of compounds strongly depended on the substitution pattern of the anilino partial structure as well as on the size of substituents. The diaryl ether partial structure had further impacts on the activity. Additionally, several physicochemical and pharmacokinetic parameters were calculated (log P, log D7.4 and ligand efficiency) or determined experimentally (passive permeability and CYP3A4 inhibition). The tert-butyl-4-{4-[2-(4-fluorophenoxy)-3-(trifluoromethyl)benzamido]phenyl}piperazine-1-carboxylate possesses high antiplasmodial activity against P. falciparum NF54 (PfNF54 IC50 = 0.2690 μM) and very low cytotoxicity (L-6 cells IC50 = 124.0 μM) resulting in an excellent selectivity index of 460. Compared to the lead structure 1 the antiplasmodial activity was improved as well as the physicochemical and some pharmacokinetic parameters.
- Dolensky, Johanna,Hermann, Theresa,Hochegger, Patrick,Kaiser, Marcel,M?ser, Pascal,Pferschy-Wenzig, Eva-Maria,Saf, Robert,Seebacher, Werner,Weis, Robert
-
-
- Hydrolysis of amides to carboxylic acids catalyzed by Nb2O5
-
Hydrolysis of amides to carboxylic acids is an industrially important reaction but is challenging due to the difficulty of cleaving the resonance stabilized amidic C-N bond. Twenty-three heterogeneous and homogenous catalysts were examined in the hydrolysis of acetamide. Results showed that Nb2O5was the most effective heterogeneous catalyst with the greatest yield of acetic acid. A series of Nb2O5catalysts calcined at various temperatures were characterized and tested in the hydrolysis of acetamide to determine the effects of crystal phase and surface properties of Nb2O5on catalytic performance. The high catalytic performance observed was attributed mainly to the facile activation of the carbonyl bond by Lewis acid sites that function even in the presence of basic inhibitors (NH3and H2O). The catalytic studies showed the synthetic advantages of the present method, such as simple operation, catalyst recyclability, additive free, solvent free, and wide substrate scope (>40 examples; up to 95% isolated yield).
- Siddiki,Rashed, Md. Nurnobi,Touchy, Abeda Sultana,Jamil, Md. A. R.,Jing, Yuan,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-Ichi
-
p. 1949 - 1960
(2021/03/26)
-
- Green synthesis method of aromatic acid
-
The invention discloses a green synthesis method of aromatic acid. Nickel-catalyzed carbonyl insertion is carried out on aryl iodine in the presence of formate, acid anhydride, a phosphine ligand andan organic solvent by using a nickel catalyst to obtain the aromatic acid. Efficient catalytic conversion is realized by utilizing the cheap nickel catalyst, the reaction conditions are mild, and theoperation is simple.
- -
-
Paragraph 0048-0122; 0196-0201; 0271-0272
(2020/05/01)
-
- Cobalt-catalyzed carboxylation of aryl and vinyl chlorides with CO2
-
The transition-metal-catalyzed carboxylation of aryl and vinyl chlorides with CO2 is rarely studied, and has been achieved only with a Ni catalyst or combination of palladium and photoredox. In this work, the cobalt-catalyzed carboxylation of aryl and vinyl chlorides and bromides with CO2 has been developed. These transformations proceed under mild conditions and exhibit a broad substrate scope, affording the corresponding carboxylic acids in good to high yields.
- Wang, Yanwei,Jiang, Xiaomei,Wang, Baiquan
-
supporting information
p. 14416 - 14419
(2020/12/01)
-
- Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
-
Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
- Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
-
supporting information
p. 4357 - 4363
(2020/07/14)
-
- Nickel-catalyzed carboxylation of aryl iodides with lithium formate through catalytic CO recycling
-
A protocol for the Ni-catalyzed carboxylation of aryl iodides with formate has been developed with good functional group compatibility for the synthesis of a variety of aromatic carboxylic acids under mild conditions. The reaction tolerates other functionalities for cross-coupling, such as aryl bromide, aryl chloride, aryl tosylate, and aryl pinacol boronate. The reaction proceeds through a carbonylation process with in situ generated carbon monoxide in the presence of a catalytic amount of acetic anhydride and lithium formate, avoiding the use of gaseous CO. The strategy of CO recycling in catalytic amounts is critical for the success of the reaction.
- Fu, Ming-Chen,Fu, Yao,Shang, Rui,Wu, Ya-Nan
-
supporting information
p. 4067 - 4069
(2020/04/20)
-
- Ni-Catalyzed Carboxylation of C(sp2)-S Bonds with CO2: Evidence for the Multifaceted Role of Zn
-
Nickel-catalyzed reductive carboxylation reactions of aryl electrophiles typically require the use of metallic reducing agents. At present, the prevailing perception is that these serve as both a source of electrons and as a source of Lewis acids that may aid CO2 insertion into the Ni-C bond. Herein, we provide evidence for the in situ formation of organometallic species from the metallic reductant, a step that has either been ruled out or has been unexplored in catalytic carboxylation reactions with metal powder reductants. Specifically, we demonstrate that Zn(0) acts as a reductant and that Zn(II) generates arylzinc species that might play a role in the C(sp2)-S carboxylation of arylsulfonium salts. Overall, the reductive Ni-catalyzed C(sp2)-S carboxylation reaction proceeds under mild conditions in a non-amide solvent, displays a wide substrate scope, and can be applied to the formal para C-H carboxylation of arenes.
- Yanagi, Tomoyuki,Somerville, Rosie J.,Nogi, Keisuke,Martin, Ruben,Yorimitsu, Hideki
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p. 2117 - 2123
(2020/02/28)
-
- Picolinamide Assisted Oxidation of CH2 Groups Bound to Organic and Organometallic Compounds Using Ferrocene as a Catalyst
-
Picolinamide group assisted sp3 C-H bond oxidation of methylene groups to the corresponding carbonyl compounds has been achieved by using simple bottle ferrocene as catalyst and Cu(OAc)2 or tert-butyl peroxybenzoate (TBPB) as oxidant under mild conditions. This method is applicable for picolinamide bound organic as well as organometallic compounds with yields in the range of 46-82%. Control experiments and mechanistic studies indicate that a radical mechanism is responsible for these oxidative transformations in which ferrocene acts as a catalyst.
- Dolui, Pritam,Hazra, Susanta,Deb, Mayukh,Elias, Anil J.
-
p. 2015 - 2021
(2019/05/16)
-
- Preparation method of substituted benzoic acid compounds
-
The invention relates to the field of production of chemical products, in particular to a preparation method of substituted benzoic acid compounds represented as general formula (II) in the description. The preparation method comprises steps as follows: corresponding substituted alkyl benzene represented as general formula (I) in the description is taken as a raw material, dilute nitric acid is taken as a reaction medium, oxygen is taken as an oxidant, an imide compound with a structure represented as formula (III) in the description or formula (IV) in the description is selected as a catalyst, all materials are subjected to catalytic oxidation in a high-pressure kettle, and substituted benzoic acid is prepared, wherein R1 is C1-C4 alkyl and R2 is halogen, nitryl, C1-C4 alkyl, methoxyl andtrifluoromethyl. The green preparation method of the substituted benzoic acid compounds is provided and has the advantages of high production purity, simple preparation, mild reaction conditions, simple aftertreatment, low cost and no pollution.
- -
-
Paragraph 0042; 0043
(2019/05/08)
-
- A O-between the - trifluoromethyl benzoic acid to synthetic method (by machine translation)
-
The present invention provides a O-between the - trifluoromethyl benzoic acid to the synthesis method, the method comprises the following steps: (1) between adjacent to methyl benzoic acid acylated preparation between neighbour methyl benzoyl chloride; (2) between the adjacent methyl benzoyl chloride to chlorine light between neighbour trichloromethyl benzoyl chloride is obtained; (3) adjacent to the trichloromethyl benzoyl chloride fluoride obtained between between neighbour trifluoromethyl methyl benzoyle fluoride; (4) adjacent to the trifluoromethyl benzoyle fluoride hydrolysis between the final product is obtained between neighbour trifluoromethyl methyl benzoic acid. The method of the invention cheap raw material, the product yield is high, the process is simple, is favorable for industrial production. (by machine translation)
- -
-
Paragraph 0031
(2017/12/29)
-
- SO2F2-Mediated One-Pot Synthesis of Aryl Carboxylic Acids and Esters from Phenols through a Pd-Catalyzed Insertion of Carbon Monoxide
-
A one-pot Pd-catalyzed carbonylation of phenols into their corresponding aryl carboxylic acids and esters through the insertion of carbon monoxide has been developed. This procedure offers a direct synthesis of aryl carboxylic acids and esters from inexpensive and abundant starting materials (phenols, SO2F2 and CO) under mild conditions. This method tolerates a broad range of functional groups and is also applicable for the modification of complicated natural products.
- Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
-
supporting information
p. 2323 - 2331
(2017/09/06)
-
- Copper-Promoted Conversion of Aromatic Amines into Trifluoromethylated Arenes: One-Pot Sandmeyer Trifluoromethylation
-
A simple copper-promoted one-pot Sandmeyer trifluoromethylation of aromatic amines with Langlois’ reagent has been demonstrated. The reaction is performed in mild reaction conditions under an air atmosphere with good substrate scope and functional group compatibility. It provides an alternative and straightforward synthetic approach to access a variety of trifluoromethylated arenes.
- Hong, Jianquan,Wang, Guifu,Huo, Lianguang,Zheng, Changge
-
supporting information
p. 1761 - 1767
(2017/09/06)
-
- Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
-
An efficient palladium-catalyzed hydroxycarbonylation reaction of arylhalides using oxalic acid as a CO source has been developed. The reaction features high safety, low catalyst loading, and a broad substrate scope, and provides a safe and tractable approach to access a variety of aromatic carboxylic acid compounds. Mechanistic studies revealed the decomposition pattern of oxalic acid.
- Shao, Changdong,Lu, Ailan,Wang, Xiaoling,Zhou, Bo,Guan, Xiaohong,Zhang, Yanghui
-
supporting information
p. 5033 - 5040
(2017/07/10)
-
- Ru(II) complexes bearing 2,6-bis(benzimidazole-2-yl)pyridine ligands: A new class of catalysts for efficient dehydrogenation of primary alcohols to carboxylic acids and H2in the alcohol/CsOH system
-
Mono-cationic Ru(II)-complexes [Ru(L)X(CH3CN)2]?X 1~4 (1, L = 2,6-bis(benzimidazol-2-yl) pyridine (L1), X = Cl; 2, L = L1, X = OTf; 3, L = 2-(N-benzyl-benzimidazole-2-yl)-6-(benzimidazole-2-yl)pyridine (L2), X = Cl; 4, L = 2,6-bis(N-benzyl-benzimidazole-2-yl)pyridine (L3), X = Cl) were prepared and fully characterized. The two acetonitrile ligands of each complex are coordinated to the metal center cis to each other. Complex 2 was also structurally characterized by X-ray crystallography. It was found that complexes 1~4 can catalyze the acceptorless dehydrogenation of primary alcohols to corresponding carboxylic acids and H2in the basic aqueous solution, and the reactivity follows the order 1 = 2 > 4 > 3. Furthermore, complexes 1 or 2 can efficiently catalyze the conversion of various primary alcohols to carboxylic acid in good yields (72%–98%) and high selectivity in an alcohol/CsOH system (1/1, mol/mol). Using an excess amount of alcohol to CsOH results in the formation of the carboxylic acid in higher yield (up to 100%, based on CsOH) and higher turnover numbers (TON ~ 10000) accompanied by the H2evolution. Complexes 1 and 2 can act as a new class of phosphine- and N-heterocycle carbene free Ru(II) complexes for efficient conversion of primary alcohols to carboxylic acids and H2in a homogeneous system.
- Dai, Zengjin,Luo, Qi,Meng, Xianggao,Li, Renjie,Zhang, Jing,Peng, Tianyou
-
-
- A 2-ethoxy carboxylic acid synthetic method of compound
-
The invention discloses a synthesis method of a 2-ethoxybenzoic acid compound. The synthesis method comprises the following steps of orderly adding aromatic acylaminopyridine-1-oxide, cuprous chloride and an organic solvent into a reactor, stirring the mixture at a room temperature for 25-35min, adding potassium carbonate into the mixture after complex precipitates are produced, heating the reaction system to a temperature of 125-135 DEG C to cause a reaction lasting for 10-15h, after the reaction, carrying out extraction, drying, condensation and chromatographic separation to obtain an ethoxylated product, and carrying out alkaline hydrolysis and acidification to obtain the 2-ethoxybenzoic acid compound. The synthesis method has the advantages of easy acquisition of raw materials, cheap catalyst, mild reaction system, operation simpleness, high yield and substrate universality. The synthesis method has the yield of 87% and can realize guide base removal under mild conditions.
- -
-
Paragraph 0022; 0058
(2017/03/24)
-
- Direct Carboxylation of Aryl Tosylates by CO2 Catalyzed by in situ-Generated Ni0
-
A novel Ni0-catalyzed carboxylation of aryl tosylates with carbon dioxide has been achieved under moderate temperatures and atmospheric pressure. In this procedure, the active Ni0 species is generated in situ by simply mixing the Ni0 precatalyst [NiBr2(bipy)] with an excess of manganese metal. This approach requires neither a glove-box nor the tedious preparation of sophisticated intermediate organometallic derivatives. This mild, convenient, and user-friendly process is successfully applied to the valorization of carbon dioxide and the synthesis of versatile reactants with broad tolerance of substituents.
- Rebih, Fatima,Andreini, Manuel,Moncomble, Aurlien,Harrison-Marchand, Anne,Maddaluno, Jacques,Durandetti, Muriel
-
supporting information
p. 3758 - 3763
(2016/03/08)
-
- An Aerobic Alternative to Oxidative Ozonolysis of Styrenes
-
A general, selective and extremely efficient procedure for the aerobic cleavage of aromatic alkenes is presented. TON values in the range 6,000,000-10,000,000 are obtained for this nickel-catalyzed reaction performed in polyethylene glycol 400 under 1 atm of molecular oxygen. Mono-, di-, tri- and tetrasubstituted styrene derivatives are oxidatively cleaved by this reproducible protocol, also suitable for larger scale (1.5 g) reactions. The presence of several functional groups (alkyl, alkoxy, halogen, trifluoromethyl) is tolerated in the substrates. The mechanistic proposal to explain the selective generation of carboxylic acids and ketones from aromatic alkenes involves the participation of the polyol solvent in the presented oxidative process.
- Urgoitia, Garazi,Sanmartin, Raul,Herrero, María Teresa,Domínguez, Esther
-
supporting information
p. 1150 - 1156
(2016/04/09)
-
- Conversion of nitroalkanes into carboxylic acids via iodide catalysis in water
-
We report a new method for the conversion of nitroalkanes into carboxylic acids that achieves this transformation under very mild conditions. Catalytic amounts of iodide in combination with a simple zinc catalyst are needed to give good conversions into the corresponding carboxylic acids.
- Marcé, Patricia,Lynch, James,Blacker, A. John,Williams, Jonathan M. J.
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p. 1013 - 1016
(2016/01/16)
-
- Selenium catalyzed oxidation of aldehydes: Green synthesis of carboxylic acids and esters
-
The stoichiometric use of hydrogen peroxide in the presence of a selenium-containing catalyst in water is here reported as a new ecofriendly protocol for the synthesis of variously functionalized carboxylic acids and esters. The method affords the desired products in good to excellent yields under very mild conditions starting directly from commercially available aldehydes. Using benzaldehyde as a prototype the gram scale synthesis of benzoic acid is described, in which the aqueous medium and the catalyst could be recycled at last five times while achieving an 87% overall yield.
- Sancineto, Luca,Tidei, Caterina,Bagnoli, Luana,Marini, Francesca,Lenardo, Eder J.,Santi, Claudio
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p. 10496 - 10510
(2015/08/06)
-
- Silver-Catalyzed C-H Trifluoromethylation of Arenes Using Trifluoroacetic Acid as the Trifluoromethylating Reagent
-
Direct trifluoromethylation of arenes using TFA as the trifluoromethylating reagent was achieved with Ag as the catalyst. This reaction not only provides a new protocol for aryl C-H trifluoromethylation, but the generation of CF3· from TFA may prove useful in other contexts and could potentially be extended to other trifluoromethylation reactions. (Chemical Equation Presented).
- Shi, Guangfa,Shao, Changdong,Pan, Shulei,Yu, Jingxun,Zhang, Yanghui
-
supporting information
p. 38 - 41
(2015/07/28)
-
- Direct carboxylation of simple arenes with CO2 through a rhodium-catalyzed C-H bond activation
-
Direct carboxylation of simple arenes under atmospheric pressure of CO2 is achieved through a rhodium-catalyzed C-H bond activation without the assistance of a directing group. Various arenes such as benzene, toluene, xylene, electron-rich or electron-deficient benzene derivatives, and heteroaromatics are directly carboxylated with high TONs. This journal is
- Suga, Takuya,Mizuno, Hajime,Takaya, Jun,Iwasawa, Nobuharu
-
supporting information
p. 14360 - 14363
(2015/02/19)
-
- Nickel-catalysed carboxylation of organoboronates
-
A nickel/N-heterocyclic carbene (NHC) catalysed carboxylation of aryl-, heteroaryl- and alkenylboronates, affording the corresponding carboxylic acids, has been developed. This transformation proceeds under one atmosphere of CO 2 with a broad range of substrates and exhibits good functional group compatibility. the Partner Organisations 2014.
- Makida, Yusuke,Marelli, Enrico,Slawin, Alexandra M. Z.,Nolan, Steven P.
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p. 8010 - 8013
(2014/07/08)
-
- Aerobic oxidation of aldehydes by visible light photocatalysis
-
An efficient and environmentally benign method for the oxidation of aldehydes to carboxylic acids has been developed. Singlet oxygen, generated by visible light in the presence of a Ru or Ir photocatalyst, reacted with aldehydes to give the corresponding carboxylic acids in excellent yields. The reaction is highly chemo-selective, in which only an aldehyde moiety is reactive even in the presence of other photo-oxidation active sites. This method is an example of an ideal green chemical reaction in the sense that molecular oxygen and visible light are key sources for the transformation.
- Iqbal, Naeem,Choi, Sungkyu,You, Youngmin,Cho, Eun Jin
-
supporting information
p. 6222 - 6225
(2013/10/22)
-
- Copper-catalyzed carboxylation of aryl iodides with carbon dioxide
-
A method for carboxylation of aryl iodides with carbon dioxide has been developed. The reaction employs low loadings of copper iodide/N,N,N′, N′-tetramethylethylenediamine (TMEDA) or N,N′- dimethylethylenediamine (DMEDA) catalyst, 1 atm of CO2, dimethylsulfoxide (DMSO) or dimethylacetamide (DMA) solvent, and proceeds at 25-70 C. Good functional group tolerance is observed, with ester, bromide, chloride, fluoride, ether, hydroxy, amino, and ketone functionalities tolerated. Additionally, hindered aryl iodides such as iodomesitylene can also be carboxylated
- Tran-Vu, Hung,Daugulis, Olafs
-
p. 2417 - 2420
(2013/10/22)
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- Sandmeyer trifluoromethylation of arenediazonium tetrafluoroborates
-
Copper capabilities: Diazonium salts are converted into the corresponding trifluoromethyl derivatives in the presence of a trifluoromethyl-copper complex generated in situ from CuSCN and the inexpensive, easy-to-use trifluoromethylating reagent Me3Si-CF3 (see scheme). This Sandmeyer-type reaction allows the straightforward synthesis of trifluoromethylated arenes and heteroarenes from the corresponding amines. Copyright
- Danoun, Grégory,Bayarmagnai, Bilguun,Grünberg, Matthias F.,Goo?en, Lukas J.
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p. 7972 - 7975
(2013/08/23)
-
- Palladium-catalyzed synthesis of aromatic carboxylic acids with silacarboxylic acids
-
Aryl iodides and bromides were easily converted to their corresponding aromatic carboxylic acids via a Pd-catalyzed carbonylation reaction using silacarboxylic acids as an in situ source of carbon monoxide. The reaction conditions were compatible with a wide range of functional groups, and with the aryl iodides, the carbonylation was complete within minutes. The method was adapted to the double and selective isotope labeling of tamibarotene.
- Friis, Stig D.,Andersen, Thomas L.,Skrydstrup, Troels
-
supporting information
p. 1378 - 1381
(2013/04/24)
-
- Effective palladium-catalyzed hydroxycarbonylation of aryl halides with substoichiometric carbon monoxide
-
A protocol for the Pd-catalyzed hydroxycarbonylation of aryl iodides, bromides, and chlorides has been developed using only 1-5 mol % of CO, corresponding to a pCO as low as 0.1 bar. Potassium formate is the only stoichiometric reagent, acting as a mildly basic nucleophile and a reservoir of CO. The substoichiometric CO could be delivered to the reaction from an acyl-Pd(II) precatalyst, which provides both the CO and an active catalyst, and thereby obviates the need for handling a toxic gas.
- Korsager, Signe,Taaning, Rolf H.,Skrydstrup, Troels
-
supporting information
p. 2891 - 2894
(2013/04/10)
-
- Kinetics and mechanism of the oxidation of substituted benzaldehydes with bis(pyridine)silver permanganate
-
The oxidation of thirty-six ortho-, meta- and para-substituted benzaldehydes by bis(pyridine)silver permanganate (BPSP) resulted in the formation of the corresponding benzoic acids. The reaction is first order with respect to both BPSP and aldehydes. The reaction is catalyzed by hydrogen ions. The rate of reaction increases with an increase in the amount of acetic acid in the solvent. The correlation analyses of the rate of oxidation of thirty-six aldehydes were performed in terms of Charton's LDR and LDRS equations. The rate of oxidation of meta- and para-substituted benzaldehydes showed excellent correlation with Charton's LDR equation. The rates of ortho-compounds showed excellent correlation with LDRS equation. The oxidation para-compounds is more susceptible to the delocalization effect. The oxidation of ortho- and meta-compounds exhibited a greater dependence on the field effect. The polar reaction constants are negative indicating an electron-deficient centre in the rate-determining step. A mechanism involving a nucleophilic attack on the carbonyl group by a permanganate-oxygen and a subsequent hydride transfer has been proposed.
- Purohit, Trupti,Banerji, Jayshree,Kotai, Laszlo,Sajo,Banerji,Sharma, Pradeep K.
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p. 1045 - 1052
(2013/01/14)
-
- Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
-
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
-
supporting information
p. 8986 - 8998,13
(2012/12/12)
-
- Silver(i)-catalyzed carboxylation of arylboronic esters with CO2
-
A variety of arylboronic esters were efficiently carboxylated with CO 2 using a simple AgOAc/PPh3 catalyst, affording the corresponding carboxylic acids in good yield. This simple and efficient silver(i) catalytic system showed wide functional group compatibility. The Royal Society of Chemistry 2012.
- Zhang, Xiao,Zhang, Wen-Zhen,Shi, Ling-Long,Guo, Chun-Xiao,Zhang, Ling-Ling,Lu, Xiao-Bing
-
supporting information; experimental part
p. 6292 - 6294
(2012/07/16)
-
- COMPOSITIONS AND METHODS FOR IMAGING
-
The present disclosure provides compositions for in vivo imaging of hydrogen peroxide; and methods for detecting hydrogen peroxide in vivo. The compositions and methods find use in various diagnostic applications, which are also provided.
- -
-
Page/Page column 29; 30
(2012/03/26)
-
- NOVEL COMPOUNDS
-
Disclosed are retinoid-related orphan receptor gamma (RORγ) modulators and their use in the treatment of diseases mediated by RORγ.
- -
-
Page/Page column 72
(2012/03/26)
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- Structure-Reactivity correlation in the oxidation of substituted benzaldehydes by tetraethylammonium chlorochromate
-
Oxidation of 36 monosubstituted benzaldehydes by tetraethylammonium chlorochromate in dimethyl sulphoxide, leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to chlorochromate and aldehydes. The reaction is promoted by H+; the H+ dependence has the form kobs = a + b[H+]. The oxidation of duteriated benzaldehyde exhibits substantial primary kinetic isotope effect. The reaction was studied in 19 different organic solvents and the effect of solvent was analyzed using Taft's and Swain's multiparametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraperametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta- substituted compounds, which display a greater dependence on the field effect. The positive value of h suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the orthosubstituents. A suitable mechanism has been proposed.
- Gehlot,Prasadrao,Sharma
-
experimental part
p. 1173 - 1178
(2012/01/05)
-
- Protolytic defluorination of trifluoromethyl-substituted arenes
-
A series of trifluoromethyl-substituted arenes were studied in their reactions with Bronsted superacids. The products from these reactions suggest the formation of reactive electrophiles, such as carbocations, acylium cations or equivalent electrophilic species. As such, Friedel-Crafts-type reactions occur between these species and arene nucleophiles. NMR studies were done, and the results suggest the formation of an acyl group from the trifluoromethyl groups in the superacid.
- Kethe, Anila,Tracy, Adam F.,Klumpp, Douglas A.
-
experimental part
p. 4545 - 4549
(2011/07/29)
-
- Copper-catalyzed aerobic oxidative synthesis of aromatic carboxylic acids
-
A simple, practical and efficient copper-catalyzed method for synthesis of aromatic carboxylic acids has been developed. The protocol uses inexpensive CuI/l-proline as the catalyst/ligand, and readily available aryl halides and malononitrile as the starting materials, and the corresponding aromatic carboxylic acids were obtained in moderate to good yields. The method is of tolerance towards functional groups in the substrates.
- Yang, Daoshan,Yang, Haijun,Fu, Hua
-
supporting information; experimental part
p. 2348 - 2350
(2011/03/21)
-
- Solvolysis of substituted benzoyl chlorides in nonionic and mixed micellar solutions
-
The solvolysis of substituted benzoyl chlorides is sensitive both to substituent electronic effects and to medium effects. The solvolysis reactions of substituted benzoyl chlorides have been analyzed in the presence of nonionic micelles. The reaction is inhibited or catalyzed depending on the reaction mechanism, dissociative or associative, respectively. The micellar effects observed can be related to the low water content and low polarity of the interface as well as an increase of the nucleophilic character of the interfacial water. Moreover, the effect of the micellar surface charge on the solvolysis mechanism with high associative character was systematically studied. Mixed micelles of nonionic-ionic surfactants with a variable ionic content were prepared and characterized regarding charge and polarity. A correlation between the net charge of the micelles and the rate constants at the micellar interface was observed. The results suggest that the transient state for this mechanism is highly stabilized in a positively charged environment while the negative surface given by anionic micelles strongly inhibit the solvolysis reaction.
- Campos-Rey,Cabaleiro-Lago,Hervés
-
experimental part
p. 14004 - 14011
(2011/02/15)
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- INHIBITORS OF STEAROYL-COA DESATURASE
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Provided herein are compounds of the formula (I): as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of diseases such as, for example, obesity.
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- Correlation analysis of reactivity in the oxidation of substituted benzaldehydes by morpholinium chlorochromate
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Oxidation of thirty six monosubstituted benzaldehydes by morpholinium chlorochromate (MCC) in dimethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to MCC. A Michaelis-Menten type kinetics is observed with respect to benzaldehydes. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form kobs = a + b [H+]. The oxidation of [2H] benzaidehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Choudhary, Anurag,Malani,Agarwal,Sharma,Sharma, Vinita
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experimental part
p. 927 - 935
(2010/07/16)
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- Structure-reactivity correlation in the oxidation of substituted benzaldehydes by 2,2-bipyridinium chlorochromate
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Oxidation of thirty six monosubstituted benzaldchydes by 2,2′-bipyridiniuin chlorochromate (BPCC) in diniethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to both BPCC and aldehydes. The reaction is promoted by hydrogen ions; the hydrogen ion dependence has the form kobs= a + b[H+]. The oxidation of [2H]benzaldehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen different organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and mete-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of orfAo-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and mem-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Sharma, Pradeep K.
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experimental part
p. 1281 - 1288
(2009/12/31)
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- Kinetics and mechanism of the oxidation of substituted benzaldehydes by tetrabutylammonium tribromide
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The oxidation of thirty-six monosubstituted benzaldehydes by tetrabutylammonium tribromide (TBATB), in aqueous acetic acid solution, leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to both TBATB and aldehydes. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride ions on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the medium. The rates of oxidation of meta- and para-substituted benzaldehydes showed excellent correlations in terms of Charton's triparametric LDR equation whereas the oxidation of ortho-substituted benzaldehydes correlated well with tetraparametric LDS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalization effect but the oxidation of ortho- and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric acceleration when ortho-substituents are present.
- Chouhan,Sharma, Monica,Sharma, Vinita
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p. 582 - 587
(2008/09/21)
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- Trifluoromethyl-substituted phenylsilanes: The regiochemical course of their metalation dictated by buttressing effects
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Triethyl[(2-trifluoromethyl)phenyl]silane reacts with the superbasic LIC-KOR mixture of butyllithium and potassium tert-butoxide exclusively at the 4-position ("meta-metalation") and not at all at the 3-position ("ortho-metalation"). Two further substrates which simultaneously contain two trifluoromethyl groups, triethyl[2,4- and 2,5-bis(trifluoromethyl) phenyl]silane, undergo deprotonation at the 5- and 4-position, respectively. Thus, a buttressing effect blocks the attack of metalating agents on the ortho position of any trifluoromethyl group which is neighbored, on the other side, by a trialkyl substituent. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Schlosser, Manfred,Heiss, Christophe,Leroux, Frederic
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p. 735 - 737
(2007/10/03)
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- Synthesis of aromatic carboxylic acids by carbonylation of aryl halides in the presence of epoxide-modified cobalt carbonyls as catalysts
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A new procedure was developed for synthesis of aromatic and heteroaromatic acids and their derivatives (esters, salts) by carbonylation of the corresponding aryl halides. The acids are selectively formed in a high yield under very mild conditions. Highly active catalytic systems, base-containing alcoholic solutions of cobalt carbonyl modified with epoxides, were used to activate aryl halides. 2005 Pleiades Publishing, Inc.
- Boyarskii,Zhesko,Lanina
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p. 1844 - 1848
(2007/10/03)
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- HIGH-PURITY (FLUOROALKYL)BENZENE DERIVATIVE AND PROCESS FOR PRODUCING THE SAME
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The process for producing a (fluoroalkyl)benzene derivative according to the present invention comprises a step of reducing the total content of group 3 to group 12 transition metals in an alkylbenzene derivative to 500 ppm or less in terms of metal atoms; a step of halogenating the branched alkyl group of the purified alkylbenzene derivative by a photohalogenation to obtain a (haloalkyl)benzene derivative; and a step of subjecting the (haloalkyl)benzene derivative to a halogen-fluorine exchange using HF in an amount of 10 mol or higher per one mole of the (haloalkyl)benzene derivative. The (fluoroalkyl)benzene derivative produced by the process is reduced in the content of impurities such as residual halogens and residual metals, and is useful as intermediates for functional chemical products for use in applications such as medicines and electronic materials.
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- Cyclodextrin effect on solvolysis of substituted benzoyl chlorides
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A kinetic study was carried out on the solvolysis of substituted benzoyl chlorides in the presence of α-, β- and γ-CD. Combination of the substituent dependent mechanism for solvolysis of benzoyl chlorides and the complexation ability of the cyclodextrin yields the following experimental behavior: (i) catalysis by β- and γ-CD for solvolysis of electron-attracting substituted benzoyl chlorides due to the reaction with its hydroxyl group C(6); (ii) absence of αCD influence on solvolysis of benzoyl chlorides with electron withdrawing substituents; (iii) inhibition of solvolysis of benzoyl chlorides with electron-donating groups. This behavior is observed for solvolysis of metal/para substituted substrates in the presence of β-CD, solvolysis of meta-substituted benzoyl chlorides in the presence of α-CD and solvolysis of para-substituted benzoyl chlorides in the presence of γ-CD. This decrease in the rate constant is a consequence of the complexation of the substrate in the cyclodextrin cavity and its low solvation ability, causing the rate of solvolysis in its interior to be negligible. (iv) The solvolysis of meta-substituted benzoyl chlorides in the presence of γ-CD yields a new behavior where the reaction of the complexed substrate is not negligible in the interior of the cyclodextrin cavity, which has been interpreted as a consequence of incomplete expulsion of hydration water from its cavity when the complexation takes place, (v) The experimental results obtained in the presence of α-CD show that weta-substituted benzoyl chlorides give rise to host : guest complexes with 1 : 1 stoichiometries, whereas those which are para-substituted cause a 2 : 1 stoichiometry to be formed. This difference in behavior has been interpreted taking into account the size of the different benzoyl chlorides and their accommodation in the α-CD cavity.
- Bascuas,Garcia-Rio,Leis
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p. 1186 - 1193
(2007/10/03)
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- Correlation analysis of reactivity in the oxidation of substituted benzaldehydes by benzyltrimethylammonium tribromide
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The oxidation of benzaldehyde and thirty-five monosubstituted benzaldehydes by benzyltrimethylammonium tribromide (BTMAB) in aqueous acetic acid leads to the formation of the corresponding benzoic acids, The reaction is first order with respect to each the benzaldehyde and BTMAB. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of benzyltrimethylammonium chloride on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the solvent. The rates of oxidation of meta- and para-substituted benzaldehydes are correlated in terms of Charton's triparametric LDR equation whereas the oxidation of ortho-substituted benzaldehydes are correlated with tetraparametric LDRS equation. The oxidation of para- substituted benzaldehydes is more susceptible to the delocalization effect than is the oxidation of ortho-and meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric hindrance by the ortho-substituents.
- Mehla, Satish K.,Kothari, Seema,Banerji, Kalyan K.
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p. 832 - 838
(2007/10/03)
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- Correlation analysis of reactivity in the oxidation of substituted benzaldehydes by pyridinium hydrobromide perbromide
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The oxidation of benzaldehyde and 35 monosubstituted benzaldehydes by pyridinium hydrobromide perbromide (PHPB) in aqueous acetic acid leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to each of the benzaldehydes and PHPB. Addition of pyridinium bromide has no effect on the rate of oxidation. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with increase in the polarity of the solvent. The rates of oxidation of meta- and para-substituted benzaldehydes were correlated in terms of Charton's triparametric LDR equation whereas those of ortho-substituted benzaldehydes were correlated with a tetraparametric LDRS equation. The oxidations of para- and ortho-substituted benzaldehydes are more susceptible to the delocalization effect while the oxidation of meta-substituted compounds displays a greater dependence on the fi eld effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric hindrance by the ortho substituents.
- Aneja, Meenakshi,Kothari, Seema,Banerji, Kalyan K.
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p. 650 - 656
(2007/10/03)
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- Kinetics and mechanism of the oxidation of substituted benzaldehydes by hexamethylenetetramine-bromine
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The oxidation of thirty-six monosubstituted benzaldehydes by hexa-methylenetetramine-bromine (HABR), in aqueous acetic acid solution, leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to HABR. Michaelis-Menten-type kinetics were observed with respect to aldehyde. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of hexamethylenetetramine on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the solvent. The rates of oxidation of meta- and para-substituted benzaldehydes showed excellent correlations in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalization effect but the oxidation of ortho- and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of γ suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric acceleration when ortho-substituents are present.
- Gangwani,Sharma,Banerji
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p. 615 - 622
(2007/10/03)
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- Kinetics and mechanism of the oxidation of substituted benzaldehydes by benzyltrimethylammonium chlorobromate
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The oxidation of 35 monosubstituted benzaldehydes by benzyltrimethylammonium chlorobromate (BTMACB) in aqueous acetic acid leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to both benzaldehyde and BTMACB. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of benzyltrimethylammonium chloride or potassium bromide on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the solvent. The rates of oxidation of meta- and para-substituted benzaldehydes were correlated in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes was correlated with the tetraparametric LDRS equation. The oxidation of para- substituted benzaldehydes is more susceptible to the delocalization effect, whereas the oxidation of ortho-and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric hindrance by the ortho substituents.
- Raju, V. Sitarama,Sharma, Pradeep K.,Banerji, Kalyan K.
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p. 3322 - 3325
(2007/10/03)
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- A general method for the alkaline cleavage of enolisable ketones
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An efficient method is described for the cleavage of enolisable aryl methyl and aryl ethyl ketones using an excess of KOH in DMF at an elevated temperature. It presents a general hydrolytic method yielding aromatic carboxylic acids, and is complementary to the widely used oxidative methods for ketone cleavage.
- Zabjek, Alenka,Petric, Andrej
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p. 6077 - 6078
(2007/10/03)
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