- Enhanced Electrophilicity of Heterobimetallic Bi-Rh Paddlewheel Carbene Complexes: A Combined Experimental, Spectroscopic, and Computational Study
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Dirhodium paddlewheel complexes are indispensable tools in modern organometallic catalysis for the controlled decomposition of diazo-compounds. Tuning the reactivity of the thus-formed transient carbenes remains an active and dynamic field of research. Herein, we present our findings that the distal metal center plays an as yet underappreciated role in modulating this reactivity. Replacement of one rhodium atom in the bimetallic core for bismuth results in the formation of a significantly more electrophilic carbene complex. Bismuth-rhodium catalysts thereby facilitate previously unknown modes of reactivity for α-diazoester compounds, including the cyclopropanation of alkenes as electron deficient as trichloroethylene. While dirhodium paddlewheel complexes remain the catalysts of choice for many carbene-mediated transformations, their bismuth-rhodium analogues exhibit complementary reactivity and show great potential for small molecule and solvent activation chemistry. DFT calculations highlight the importance of metal-metal bonding interactions in controlling carbene electrophilicity. The paucity of these interactions between the 4d orbitals of rhodium and the 6p orbitals of bismuth results in weaker π-back-bonding interactions for bismuth-rhodium carbene complexes compared to dirhodium carbene complexes. This leads to weakening of the rhodium-carbene bond and to a more carbene-centered LUMO, accounting for the observed enhancement in bismuth-rhodium carbene electrophilicity. These findings are supported by a detailed spectroscopic study of the "donor-donor" carbene complexes Rh2(esp)2C(p-MeOPh)2 (19) and BiRh(esp)2C(p-MeOPh)2 (20), employing a combination of UV-vis and resonance Raman spectroscopy. The results reveal that carbene chemoselectivity in MRh(L)4 catalysis can be modulated to a previously unrecognized extent by the distal metalloligand.
- Collins, Lee R.,Van Gastel, Maurice,Neese, Frank,Fürstner, Alois
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- Microwave synthesis of chloroacetic acid with acetic anhydride catalyzing chlorination of acetic acid
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In this paper, the chloroacetic acid has been synthesized with the acetic anhydride catalyzing chlorination of acetic acid by microwave irradiation. The volume fraction of acetic anhydride in acetic acid, reaction time, microwave power and reaction temperature have been investigated in the self-designed experimental device. The results showed that the optimum conditions were the volume fraction of acetic anhydride in acetic acid of 20 %, reaction time of 3.5 h, microwave power of 300 W, reaction temperature of 95 °C, the yield of chloroacetic acid was 94.31 % and the selectivity was 93.01 %. Compared with ordinary heating, the selectivity and the reaction rate of using microwave irradiation were apparently improved.
- Wang, Li-Sheng,Song, Guo-Qiang,Meng, Ying,Li, Shou-Gao,Li, Fu-Xiang
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- Discovery of novel triazolophthalazine derivatives as DNA intercalators and topoisomerase II inhibitors
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A new series of triazolophthalazine derivatives was designed and synthesized as topoisomerase II (Topo II) inhibitors and DNA intercalators. The synthesized derivatives were evaluated in vitro for their cytotoxic activities against three human cancer cell lines: HepG2, MCF-7, and HCT-116 cells. Compound IXb was the most potent counterpart with IC50 values of 5.39 ± 0.4, 3.81 ± 0.2, and 4.38 ± 0.3 μM, as it was about 1.47, 1.77, and 1.19 times more active than doxorubicin (IC50 = 7.94 ± 0.6, 6.75 ± 0.4, and 5.23 ± 0.3 μM) against HepG2, MCF-7, and HCT-116 cells, respectively. Additionally, the binding affinity of the synthesized compounds toward the DNA molecule was assessed using the DNA/methyl green assay. Compound?IXb showed an excellent DNA binding affinity with an IC50 value of 27.16 ± 1.2 μM, which was better than that of the reference drug doxorubicin (IC50 = 31.02 ± 1.80 μM). Moreover, compound IXb was the most potent member among the tested compounds when investigated for their Topo II inhibitory activity. Furthermore, compound IXb induced apoptosis in HepG2 cells and arrested the cell cycle at the G2/M phase. Additionally, compound IXb showed Topo II poisoning effects at 2.5 μM and Topo II catalytic inhibitory effects at 5 and 10 μM. Finally, molecular docking studies were carried out against the DNA–Topo II complex and DNA, to investigate the binding patterns of the designed compounds.
- Sakr, Helmy,Ayyad, Rezk R.,El-Helby, Ali A.,Khalifa, Mohamed M.,Mahdy, Hazem A.
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- Activation reactions of 1,1-dialkoxoalkanes and unsaturated O-donors by titanium tetrafluoride
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The reactivity of TiF4 with a variety of non cyclic 1,1-dialkoxoalkanes [CH2(OR)2, R = Me, Et, Me 2C(OMe)2, MeCH(OEt)2, ClCH2CH(OEt) 2, CH(OMe)3, PhCCCH(OEt)2], 1,3-dioxolane, N2CHCO2Et and 1,2-epoxybutane has been investigated. Activation, including fragmentation and/or rearrangement of the organic moiety, has been observed at room temperature in some cases; it generally occurs unselectively via C-O bond fission and the formation of new C-O, C-H and C-C bonds. Small differences in the structure of the organic substrate may determine significant differences in the reactivity with TiF4.
- Marchetti, Fabio,Pampaloni, Guido,Biancalana, Lorenzo
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- An efficient chemoenzymatic synthesis of the bactericide lapyrium chloride
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An efficient route for large-scale preparation of lapyrium chloride, a broad-spectrum antimicrobial surfactant, was developed from chloroacetic acid in four steps, three of them enzymatic. Due to the chemoselective behavior of the biocatalysts, lapyrium chloride was obtained in a high degree of purity and yield, from mild reaction conditions and following a low environmental impact methodology. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
- Rustoy, Eduardo M.,Baldessari, Alicia
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- Catalytic esterifications of carboxylic acids and alcohols by sodium bisulfate monohydrate
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The efficient esterification of primary and secondary alcohols with aliphatic carboxylic acids in the presence of a catalytic amount of sodium bisulfate monohydrate to afford the corresponding esters in high yields.
- Li, Yi-Qun
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- Using remote substituents to control solution structure and anion binding in lanthanide complexes
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A study of the anion-binding properties of three structurally related lanthanide complexes, which all contain chemically identical anion-binding motifs, has revealed dramatic differences in their anion affinity. These arise as a consequence of changes in the substitution pattern on the periphery of the molecule, at a substantial distance from the binding pocket. Herein, we explore these remote substituent effects and explain the observed behaviour through discussion of the way in which remote substituents can influence and control the global structure of a molecule through their demands upon conformational space. Peripheral modifications to a binuclear lanthanide motif derived from α,α′-bis(DO3 Ayl)-m-xylene are shown to result in dramatic changes to the binding constant for isophthalate. In this system, the parent compound displays considerable conformational flexibility, yet can be assumed to bind to isophthalate through a well-defined conformer. Addition of steric bulk remote from the binding site restricts conformational mobility, giving rise to an increase in binding constant on entropic grounds as long as the ideal binding conformation is not excluded from the available range of conformers.
- Tropiano, Manuel,Blackburn, Octavia A.,Tilney, James A.,Hill, Leila R.,Placidi, Matteo P.,Aarons, Rebecca J.,Sykes, Daniel,Jones, Michael W.,Kenwright, Alan M.,Snaith, John S.,Sorensen, Thomas Just,Faulkner, Stephen
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- A simple criterion for gas chromatography/mass spectrometric analysis of thermally unstable compounds, and reassessment of the by-products of alkyl diazoacetate synthesis
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Rationale: A principal limitation of gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) is the thermal instability of analytes. We propose that the injector and column temperatures should not exceed the atmospheric pressure boiling point, without decomposition, of the highest homologue of the series being analyzed, instead of the time-consuming procedure of obtaining chromatograms using different temperatures. Methods: A series of thermally unstable diazocarbonyl compounds, alkyl diazoacetates (predicted limit of stability approx. 140 °C, the boiling point of ethyl diazoacetate), was selected for GC/MS analysis using standard equipment. Different GC separation conditions were selected so that the retention temperatures of target compounds were both below and above 140°C. Results: Analyzing alkyl diazoacetates within their thermal stability range permitted reanalysis of their typical synthesis by-products. No dialkyl fumarate or maleate impurities, principal decomposition products which have often been reported previously, were found. Instead, alkyl esters of glycolic acid nitrate, O2NOCH 2CO2R, and 'pseudo-dimeric' products, ROCO[C 2H3NO]CO2R, were discovered for the first time. Conclusions: Avoiding the decomposition of thermally unstable organic compounds during GC and/or GC/MS analysis requires estimating their degradation temperature limits. This limit can be estimated as being equal to the atmospheric pressure boiling point of the highest homologue in the homologous series under consideration that does not decompose on boiling. Copyright
- Kornilova, Tatiana A.,Ukolov, Anton I.,Kostikov, Rafael R.,Zenkevich, Igor G.
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- REDUCTIVE DEHALOGENATION OF α-HALOGENATED CARBONYL AND CYANO COMPOUNDS WITH THE HEXAMETHYLDISILANE/TETRAKIS(TRIPHENYLPHOSPHINE)PALLADIUM SYSTEM
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Treatment of α-halogenated carbonyl or cyano compounds with hexamethyldisilane in the presence of catalytic amounts of tetrakis(triphenylphosphine)-palladium gives the corresponding parent carbonyl or cyano compounds in excellent yields via oxy-?-allyl(trimethylsilyl)palladium intermediates.
- Urata, Hisao,Suzuki, Hiroharu,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
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- CHLORINATING PROPERTIES OF THE TRIMETHYLCHLOROSILANE-POTASSIUM BROMATE-DMF SYSTEM
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β-Dicarbonyl compounds such as ethyl acetoacetate, dimedone, and Meldrum's acid derivatives undergo monochlorination by the action of a mixture of ClSiMe3 and KBrO3 in DMF at ca. 20 deg C. Keywords: β-dicarbonyl compounds, monochlorination.
- Zav'yalov, S. I.,Sitkareva, I. V.,Ezhova, G. I
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- Inhibition of acetylcholinesterase by coumarin-linked amino acids synthetized via triazole associated with molecule partition coefficient
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A previous study for the identification of acetylcholinesterase (AChE) inhibitors demonstrated that the hybrid between tyrosol, the 1,2,3-triazole nucleus, and the coumarin group, namely 7-({1-[2-(4-hydroxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methoxy)-4-methyl-2H-chromen-2-one (10), has a high enzyme inhibitory activity. Here, we synthesized analogues of 10 via triazole with pharmacophoric groups represented by tyrosine, phenylalanine, tryptophan, and glycine in addition to evaluating the impact of coumarin-linked amino acids on AChE inhibition. We obtained eight triazoles, six of which are undescribed. In general, the presence of carboxylic acid decreased the inhibitory activity, while aromatic amino acids increased enzymatic inhibition compared to glycine. The derivative containing tyrosine, structurally most similar to 10, presented the lowest inhibition percentage, indicating that phenolic hydroxyl is not the preponderant factor for inhibition. Molecular docking was not enough to explain in vitro experiments. On the other hand, MlogP (logP calculated by the Moriguchi method) was related positively to enzymatic inhibition. To increase the hydrophobicity of the molecules, we tested the esterified triazole derivatives comparatively with the enzyme. The compound ethyl 2-(4-(((4-methyl-2-oxo-2H-chromen-7-yl)oxy)methyl)- 1H-1,2,3-triazol-1-yl)acetate (6) presented an increment of inhibitory activity of 46.97 ± 1.75% at 100 μmol L-1. We also associated the best activity with the lowest van der Waals volume and molar mass values.
- De Sousa, Bianca L.,Leite, Jo?o P.V.,Mendes, Tiago A.O.,Varej?o, Eduardo V.V.,Chaves, Anna C.S.,da Silva, Júnio G.,Agrizzi, Ana P.,Ferreira, Priscila G.,Pilau, Eduardo J.,Silva, Evandro,dos Santos, Marcelo H.
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p. 652 - 664
(2021/02/16)
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- New Diesters Derived from Piperine: In silico Study and Evaluation of Their Antimicrobial Potential
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Piperine, previously extracted from black pepper (Piper nigrum L.), was used as a precursor for the synthesis of twelve new diester derivatives. The final products were obtained through the bimolecular nucleophilic substitution reaction (SN2) of the alkyl 2-chloroacetates and the salt of piperic acid, obtained from the basic hydrolysis of piperine. The compounds were synthesized with yields of 55-84% and characterized by infrared spectroscopy and 1H and 13C nuclear magnetic resonance. The evaluation of the compounds’ potential as new drug candidates was done through an in silico study of ADME properties (absorption, distribution, metabolization and excretion) and evaluation of antimicrobial activity against bacterial strains (Staphylococcus aureus and Pseudomonas aeruginosa), yeasts (Candida albicans and Candida tropicalis) and filamentous fungi (Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger). The in silico study showed that the compounds were good drug candidates and antimicrobial evaluation demonstrated that 9 of the 12 compounds exhibited a minimum inhibitory concentration (MIC) ranging 1024-256 μg mL?1
- Barbosa-Filho, José M.,Brand?o, Maria Cláudia R.,Lima, Edeltrudes O.,Lira, Bruno F.,Neto, Hermes D.,Souza, Helivaldo D. S.,Trindade, Emmely O.,de Athayde-Filho, Petr?nio F.
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p. 1668 - 1678
(2020/10/09)
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- Synthesis, in silico Study and Antimicrobial Evaluation of New Diesters Derived from Phthaloylglycine
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New diesters derived from phthaloylglycine (7a-7i) were synthesized and their structures characterized by infrared, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The compounds were evaluated in an in silico study, which demonstrated positive features indicating a possible drug candidate. The diesters showed antifungal activity ranging from moderate to strong against strains of Candida. Compounds 7a, 7b, 7c, 7e and 7i had a moderate minimum inhibitory concentration (MIC) of 1024 μg mL?1 against all fungal strains, while 7h showed a very good MIC of 256 μg mL?1 against Candida albicans, Candida parapsilosis and Candida krusei and 64 μg mL?1 against Candida tropicalis. However, only 7h and 7i were able to inhibit bacterial growth of strains of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli with an MIC of 1024 μg mL?1
- Alves, Francinara S.,Barbosa-Filho, José M.,Cordeiro, Laísa V.,Huang, Min-Fu N.,Lima, Edeltrudes O.,Neto, Hermes Diniz,Souza, Helivaldo D. S.,Trindade, Emmely O.,de Athayde-Filho, Petr?nio F.,de Lima, Priscila S. V.,de Oliveira, Rafael F.,de Sousa, Abra?o P.
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p. 953 - 962
(2020/10/14)
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- Synthesis method of diethyl cyanomethylphosphonate
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The invention discloses a synthesis method of diethyl cyanomethylphosphonate. The synthesis method comprises the following steps: carrying out an esterification reaction on chloroacetic acid and ethanol to obtain ethyl chloroacetate; reacting the ethyl chloroacetate with ammonia water to generate chloroacetamide; adding phosphorus pentoxide into the chloroacetamide, performing heating dehydration,distilling out chloroacetonitrile while heating, and finally performing reduced pressure distillation to enable the chloroacetonitrile to be completely distilled out; transferring the chloroacetonitrile into a synthesis reaction kettle, adding a catalyst tetrabutylammonium iodide, heating, dropwise adding triethyl phosphite, and controlling the internal temperature for a reaction to obtain a crude product; and transferring the crude product into a high-purity rectifying tower, and performing purification to respectively rectify triethyl phosphite and diethyl cyanomethylphosphonate.
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Paragraph 0016-0017; 0020-0021; 0024-0025; 0028-0029
(2020/05/01)
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- Betaine hydrochloride salt synthesis method
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Betaine hydrochloride synthetic method, are sequentially added to the reaction bottle benzenedimethanol acetic acid, catalyst, ethanol, then heating up 100 — 115 °C reflux, molecular sieve dehydration backflow place, 2 — 8 hours after the completion of the reaction, the reaction solution is washed with water 2 times, divided chloroethyl ethyl acetate by reduced pressure distillation, the chloropropyl acetic acid ethyl ester are added to a reaction in the bottle, add a certain amount of water, the beginning of the access trimethylamine gas, maintained in the 20 — 45 °C, 2 — 6 hours of reaction, the temperature of the hydrochloric acid is then added to the hydrolysis, distilling the water and ethanol, cooling 10 — 15 °C crystallization centrifugation to obtain the betaine hydrochloride. The present invention made from the chloroacetic acid and ethanol raw material synthetic a chloroethyl ethyl acetate, to obtain pure chloro ethyl acetate through and dimethylamine synthesizing betaine ethyl ester hydrochloride, in the presence of hydrochloride heating water out to ethanol, concentrated liquid cooling to separate out betaine hydrochloride, prepared by the method of the betaine hydrochloride purity 99% or more, the yield of 97% or more, and there will not be any inorganic salt solid waste.
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Paragraph 0008; 0010; 0012
(2019/07/08)
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- Preparation method of novel thermosensitive ionic liquid and method for synthesizing chloracetate catalytically
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The invention discloses an acid functionalized-temperature controlled ternary heteropolyacid ionic liquid and a preparation method thereof, as well as an esterification method for synthesizing chloracetate catalytically. The structural formula of the heteropolyacid ionic liquid is as shown in a formula (I). The ionic liquid has a temperature responding characteristic during esterification reactionof chloroacetic acid and chloroacetic acid, is mixed with a reactant as one phase at the reaction temperature, and is further divided into two phases with the product when the temperature is reducedto a room temperature after the reaction. A catalyst and a reaction product can be separated quickly by simple filtration. The ionic liquid not only has the advantages of being convenient to recover and free of waste acid emission, but also has the characteristics of being high in esterification efficiency, good in repeated using performance and the like.
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Paragraph 0031
(2019/04/02)
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- Magnetically recoverable AlFe/Te nanocomposite as a new catalyst for the facile esterification reaction under neat conditions
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In this work, a new Fe3O4/AlFe/Te nanocomposite was synthesized by a one-step sol–gel method. The Fe3O4 magnetic nanoparticles (MNPs) were prepared and then mixed with aluminum telluride (Al2Te3) in an alkali medium to produce the desired catalyst. After characterization of the Fe3O4/AlFe/Te nanocomposite by SEM, TEM, EDS, XRD, and ICP analyses, it was used in the esterification reaction. This heterogeneous catalyst showed high catalytic activity in the esterification of commercially available carboxylic acids with various alcohols to produce the desired esters at high conversions under neat conditions. The Fe3O4/AlFe/Te nanocomposites were separated from the reaction mixture via an external magnet and re-used 8 times without significant loss of catalytic activity.
- Alavi, Seyed Jamal,Sadeghian, Hamid,Seyedi, Seyed Mohammad,Eshghi, Hossein,Salimi, Alireza
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- Preparation method for 2,4-dichlorophenol, and preparation method for 2,4-dichlorophenolate
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The invention provides a preparation method for 2,4-dichlorophenol. The preparation method comprises the following steps: S) adding phenol, a promoter and sulfuryl chloride into an organic solvent andcarrying out chlorination under low temperature conditions to obtain 2,4-dichlorophenol, wherein the promoter is one or more selected from the group consisting of dimethyl sulfide, phenyl sulfide andisopropyl ether. Compared with the prior art, the preparation method provided by the invention has the advantage that selectivity is improved due to the reaction under low temperature conditions; andthe promoter is added at the same time to ensure a reaction rate.
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Paragraph 0046; 0047
(2018/09/08)
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- Preparation method for 2,4-dichlorophenoxyacetic acid
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The invention provides a preparation method for 2,4-dichlorophenoxyacetic acid. The preparation method comprises the following steps: A) reacting halogenated acetic acid with alcohol so as to obtain halogenated acetate, and reacting phenol with alkali to obtain phenolate; B) reacting halogenated acetate with phenolate to obtain phenoxyacetate; C) hydrolyzing phenoxyacetate to obtain phenoxyaceticacid; and D) chlorinating phenoxyacetic acid under the action of a catalyst to obtain 2,4-dichlorophenoxyacetic acid, wherein the catalyst is one or more selected from the group consisting of ferric trichloride, aluminum trichloride, boron trifluoride, niobium pentachloride, trifluoromethanesulfonate, alumina, ferric oxide, boron trioxide, niobium pentoxide, diphenyl ether, diphenyl sulfide, diphenyl disulfide, dimethyl sulfide and dimethyl disulfide. According to the invention, phenolate reacts with halogenated acetate to obtain phenoxyacetate, then phenoxyacetate is hydrolyzed to obtain phenoxyacetic acid, and phenoxyacetic acid is chlorinated under the action of the specific catalyst so as to obtain 2,4-dichlorophenoxyacetic acid. The preparation method of the invention uses the specific catalyst, and has the advantages of good reaction selectivity, few by-products and high yield.
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Paragraph 0050; 0051; 0052; 0053; 0054; 0055
(2018/09/08)
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- Preparation method for 2,4-dichlorophenoxyacetic acid
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The invention provides a preparation method for 2,4-dichlorophenoxyacetic acid, belonging to the technical field of organic synthesis. The preparation method comprises the following steps: a) reactinghalogenated acetate with 2,4-dichlorophenolate in the presence of a phase-transfer catalyst so as to obtain 2,4-dichlorophenoxyacetate; and b) hydrolyzing 2,4-dichlorophenoxyacetate so as to obtain 2,4-dichlorophenoxyacetic acid. According to the invention, oil-phase halogenated acetate reacts with 2,4-dichlorophenolate under the action of the phase-transfer catalyst to prepare 2,4-dichlorophenoxyacetate, and then 2,4-dichlorophenoxyacetate is hydrolyzed to obtain 2,4-dichlorophenoxyacetic acid and corresponding alcohols. Under the action of the phase-transfer catalyst, few hydrolysis by-products are produced during a reaction, fast reaction speed and high conversion rate and yield are obtained, and the amount of produced waste water is low; so industrial application of the preparation method can be easily implemented.
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Paragraph 0047; 0048
(2018/09/08)
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- A method for preparing 2, 4 - dichlorophenoxyacetic acid (by machine translation)
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The invention provides a 2, 4 - dichlorophenoxyacetic acid preparation method, comprising: A) a halogenated acetic acid with the monoester should be halogenated acetate; phenol with alkali reaction to obtain the phenoxide; B) halogenated acetate and phenol salt reaction to obtain the phenoxyacetic acid ester; C) phenoxyacetic acid ester under the effects of catalyst chloride to obtain 2, 4 - dichlorophenoxy ester; said catalyst selected from iron trichloride, aluminum trichloride, boron trifluoride, five [...], trifluoromethyl sulfonate, aluminum oxide, ferric oxide, boron trioxide, niobium pentoxide, diphenyl ether, diphenyl sulfide, benzoin two sulfide, dimethyl sulfide and dimethyl sulfide in one or several of the D) 2, 4 - dichlorophenoxy ester hydrolysis to obtain 2, 4 - dichloro acid. This invention adopts the specific reaction routes and chlorinated using a specific catalyst, good reaction selectivity, few by-products, high yield. (by machine translation)
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Paragraph 0051; 0052
(2018/09/08)
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- Preparation method for 2,4-dichlorophenoxyacetic acid
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The invention provides a preparation method for 2,4-dichlorophenoxyacetic acid, belonging to the technical field of organic synthesis. The preparation method comprises the following steps: a) reactinghalogenated acetate with an anhydrous 2,4-dichlorophenolate solid so as to obtain 2,4-dichlorophenoxyacetate; and b) hydrolyzing 2,4-dichlorophenoxyacetate so as to obtain 2,4-dichlorophenoxyacetic acid. According to the invention, the anhydrous 2,4-dichlorophenolate solid reacts with halogenated acetate to prepare 2,4-dichlorophenoxyacetate, and then 2,4-dichlorophenoxyacetate is hydrolyzed to obtain 2,4-dichlorophenoxyacetic acid and corresponding alcohols. The mass transfer effect of a solid-liquid reaction in the invention is good; few hydrolysis by-products are produced during the reaction; fast reaction speed and high conversion rate and yield are obtained; the amount of produced waste water is low; so industrial application of the preparation method can be easily implemented.
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Paragraph 0046; 0047
(2018/09/08)
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- Preparation method for 2,4-dichlorophenoxyacetic acid
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The invention provides a preparation method for 2,4-dichlorophenoxyacetic acid. The preparation method comprises the following steps: A) reacting C2 or above-C2 alcohol with halogenated acetic acid soas to obtain halogenated acetate; B) reacting halogenated acetic acid with 2,4-dichlorophenolate so as to obtain 2,4-dichlorophenoxyacetate; and C) hydrolyzing 2,4-dichlorophenoxyacetate so as to obtain 2,4-dichlorophenoxyacetic acid. According to the invention, C2 or above-C2 alcohol reacts with halogenated acetic acid to obtain a halogenated acetate intermediate, the intermediate has good stability, few reaction by-products are produced, and high yield is realized; then the intermediate further reacts with 2,4-dichlorophenolate to obtain 2,4-dichlorophenoxyacetate; and finally, 2,4-dichlorophenoxyacetate is hydrolyzed to obtain 2,4-dichlorophenoxyacetic acid. Through a specific reaction route of the invention, the finally prepared 2,4-dichlorophenoxyacetic acid has high purity and yield, few by-products are produced, the reaction route is simple, and the application of the preparation method is facilitated.
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Paragraph 0046; 0047; 0055
(2018/09/08)
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- Preparation method for 2,4-dichlorophenoxyacetic acid
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The invention provides a preparation method for 2,4-dichlorophenoxyacetic acid. The preparation method comprises the following steps: a) reacting haloacetic acid with 2,4-dichlorophenolate in a strong-polarity solvent so as to obtain 2,4-dichlorophenoxy acetate; and B) hydrolyzing 2,4-dichlorophenoxyacetate so as to obtain 2,4-dichlorophenoxyacetic acid. According to the invention, the strong-polarity solvent is utilized, so the mass transfer effect of the reaction is improved, reaction time is reduced, the reaction is more complete, and the conversion rate and yield of the reaction are greatly improved.
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Paragraph 0032; 0033
(2018/09/29)
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- Synthesis method of triethyl phosphonoacetate
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Relating to the field of organic compound synthesis, the invention provides a synthesis method of triethyl phosphonoacetate. Triethyl phosphate and ethyl chloroacetate are taken as the raw materials to carry out Michael arbuzov rearrangement reaction, thus obtaining triethyl phosphonoacetate. The chemical reaction formulas of the synthesis method are: CH2ClCOOH+C2H5OH to C4H7ClO2+H2O, C4H7ClO2+C6H15O3P to C8H17O5P+C2H5Cl. The method provided by the invention solves the problems of high energy consumption, high cost and low product purity in the traditional process, also solves the problem of byproduct application in a synthetic environment, and achieves good economic and social benefits.
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Paragraph 0017; 0019; 0020; 0024; 0025; 0029; 0030
(2017/08/27)
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- 1-H phenyltheophylline and the three kinds of the nitrogen production method of [...] ester
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The invention discloses a production method of 1-H benzotriazole acetate. The method comprises the steps of synthesizing ethyl chloroacetate and synthesizing 1-H benzotriazole ethyl acetate; firstly adding trichloromethane and a catalyst namely triethylamine, dropping a trichloromethane solution containing chloroacetyl chloride, removing triethylamine hydrochloride by filtration, and evaporating filtrate to dryness by using a rotary evaporator, thereby obtaining a residue namely ethyl chloroacetate; adding absolute ethyl alcohol, benzotriazole and sodium hydroxide, filtering an ethanol solution containing ethyl chloroacetate to obtain a generated inorganic salt, concentrating the filtrate, precipitating crystals, and filtering to obtain a product. Compared with conventional production methods, the method disclosed by the invention can be used for greatly shortening the production time and greatly improving the production efficiency; 1-H benzotriazole acetate produced by using the method has good thermal stability and oil solubility, can be used for significantly improving the extreme pressure property of liquid paraffin under an appropriate additive amount and improving the bearing capacity of liquid paraffin, and can reach a yield of more than 90%.
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Paragraph 0018
(2017/02/17)
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- Synthesis and biological evaluation of new quinoxaline derivatives of ICF01012 as melanoma-targeting probes
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The aim of this study was the synthesis and pharmacokinetic selection of a best melanin-targeting ligand for addressing anticancer agents to pigmented melanoma. Seven quinoxaline carboxamide derivatives were synthesized and radiolabeled with iodine-125. Biodistribution studies of compounds [ 125I]1a-g performed in melanoma-bearing mice tumor showed significant tumor uptake (range 2.43-5.68%ID/g) within 1 h after i.v. injection. Fast clearance of the radioactivity from the nontarget organs mainly via the urinary system gave high tumor-to-blood and tumor-to-muscle ratios. Given its favorable clearance and high tumor-melanoma uptake at 72 h, amide 1d was the most promising melanoma-targeting ligand in this series. Compound 1d will be used as building block for the design of new melanoma-selective drug delivery systems.
- El Aissi, Radhia,Liu, Jianrong,Besse, Sophie,Canitrot, Damien,Chavignon, Olivier,Chezal, Jean-Michel,Miot-Noirault, Elisabeth,Moreau, Emmanuel
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supporting information
p. 468 - 473
(2014/06/09)
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- SYNTHESIS OF CYANOCARBOXYLIC ACID ALKYL ESTERS
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Provided is a process for obtaining a compound of formula (I): N≡C-CH2-A-C(O)-OR, wherein Hal is halogen selected from F, Cl, Br or I, A denotes a bond or a divalent spacer selected from alkylene and arylene groups, and R is a C1-4 alkyl group, by reacting a compound of formula (II): Hal-CH2-A-C(O)-OR, wherein Hal is a halogen atom selected from F, Cl, Br and I, and wherein A and R are as defined above, with hydrogen cyanide in the presence of a first base, wherein the molar ratio between hydrogen cyanide and said first base is from 1:0.3 to 1:0.95 and the molar ratio between hydrogen cyanide to the compound of formula (II) is at least 1:1.
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Page/Page column 35-36
(2013/08/28)
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- PROCESS AND EQUIPMENT FOR THE PREPARATION OF HALOCARBOXYLIC ACID ALKYL ESTERS
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Provided is a reactive distillation and equipment to obtain a compound of formula (II) Hal-CH2-A-C(O)-OR, wherein Hal is halogen selected from F, CI, Br or I, A denotes a bond or a divalent spacer selected from alkylene and arylene groups, and R is C1-4 alkyl group.
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Page/Page column 21; 22
(2013/08/28)
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- Preparation of esters of mono- or dicarboxylic non-aromatic and aromatic acids
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The present invention relates to a method for preparing a carboxylic acid ester, wherein a carboxylic acid and/or a salt thereof is reacted with an alcohol in the presence of hydrogen chloride (HCl) and water to form the carboxylic acid ester, wherein the reaction is carried out using a starting reaction system wherein the molar ratio of HCl to carboxylic acid is at least 0.075 : 1 and the molar ratio of water to carboxylic acid is at least 0.25 : 1.
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Page/Page column 5
(2012/06/30)
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- Convenient preparation of benzylseleno- and phenylselenoalkanoic acids: Reagents for synthesis of organoselenium compounds
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An efficient and operationally simple route to benzylseleno- and phenylselenoalkanoic acids from ethyl benzyl/phenylselenoalkanoates is described. This involves preparation of ethyl benzyl/phenylselenoalkanoates as substrates by reaction of dibenzyl/diphenyl diselenide and sodium borohydride with ethyl chloroalkanoates in ethanol followed by basic hydrolysis and subsequent acidification. Copyright Taylor & Francis Group, LLC.
- Bhalla, Aman,Sharma, Sitansh,Bhasin, Kuldip K.,Bari, Shamsher S.
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p. 783 - 793
(2007/10/03)
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- Competing reactions of secondary alcohols with sodium hypochlorite promoted by phase-transfer catalysis
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(Chemical Equation Presented) With aqueous hypochlorite and a phase transfer catalyst, secondary alcohols undergo hitherto unreported free radical reactions that compete with and effectively limit traditional ketone syntheses. Product mixture profiles are determined by reactant ratios, organic cosolvent, and availability of oxygen to the system. Under argon, over half of substrate alcohols, PhCH(OH)R, are converted to benzaldehyde and free radical products through β-scission of intermediate alkyl hypochlorites. Secondary alcohols with R containing three or more carbons also may undergo δ chlorination.
- Bright, Zack R.,Luyeye, Cedric R.,Morton, Angela Ste. Marie,Sedenko, Marina,Landolt, Robert G.,Bronzi, Matthew J.,Bohovic, Katherine M.,Gonser, M. W. Alex,Lapainis, Theodore E.,Hendrickson, William H.
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p. 684 - 687
(2007/10/03)
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- Mechanisms of solvolyses of acid chlorides and chloroformates. Chloroacetyl and phenylacetyl chloride as similarity models
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Rate constants and product selectivities (S = ([ester product]/[acid product]) × ([water]/[alcohol solvent]) are reported for solvolyses of chloroacetyl chloride (3) at -10 °C and phenylacetyl chloride (4) at O °C in ethanol/and methanol/water mixtures. Additional kinetic data are reported for solvolyses in acetone/water, 2,2,2-trifluoroethanol(TFE)/water, and TFE/ethanol mixtures. Selectivities and solvent effects for 3, including the kinetic solvent isotope effect (KSIE) of 2.18 for methanol, are similar to those for solvolyses of p-nitrobenzoyl chloride (1, Z = NO2); rate constants in acetone/water are consistent with a third-order mechanism, and rates and products in ethanol/and methanol/water mixtures can be explained quantitatively by competing third-order mechanisms in which one molecule of solvent (alcohol or water) acts as a nucleophile and another acts as a general base (an addition/elimination reaction channel). Selectivities increase for 3 as water is added to alcohol. Solvent effects on rate constants for solvolyses of 3 are very similar to those of methyl chloroformate, but acetyl chloride shows a lower KSIE, and a higher sensitivity to solvent-ionizing power, explained by a change to an SN2/SN1 (ionization) reaction channel. Solvolyses of 4 undergo a change from the addition/elimination channel in ethanol to the ionization channel in aqueous ethanol (80% v/v alcohol). The reasons for change in reaction channels are discussed in terms of the gas-phase stabilities of acylium ions, calculated using Gaussian 03 (HF/6-31G(d), B3LYP/6-31G(d), and B3LYP/6-311G(d,p) MO theory).
- Bentley, T. William,Harris, H. Carl,Ryu, Zoon Ha,Lim, Gui Taek,Sung, Dae Dong,Szajda, Stanley R.
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p. 8963 - 8970
(2007/10/03)
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- Activation of alkyl halides via a silver-catalyzed carbene insertion process
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The silver complex [HB(3,5-(CF3)2Pz)3]Ag(THF) featuring a highly fluorinated tris(pyrazolyl)borate ligand catalyzes the formation of aliphatic carbon-halogen bond activation products under remarkably mild conditions. For example, the reaction between CHCl3 and ethyl diazoacetate (EDA) at room temperature in the presence of the silver catalyst afforded HClC(CO2Et)CCl2H in 60% yield. The presence of β-hydrogens on the alkyl halide leads to net hydrogen halide addition to the carbene and an alkene. Copyright
- Dias, H. V. Rasika,Browning, R. Greg,Polach, Sharon A.,Diyabalanage, Himashinie V. K.,Lovely, Carl J.
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p. 9270 - 9271
(2007/10/03)
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- Thiazole derivatives
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Compounds of the formula: as well as pharmaceutically usable salts and esters thereof, wherein R1, R2 and R3 have the significance ascribed herein, inhibit binding of adhesive proteins to the surface of different types of cell and accordingly influence cell-cell and cell-matrix interactions. These compounds can be used in the form of pharmaceutical preparations for the control or prevention of neoplasms, tumor metastasing, tumor growth, osteoporosis, Paget's disease, diabetic retinopathy, macular degeneration, restenosis following vascular intervention, psoriasis, arthritis, fibrosis, kidney failure, as well as infection caused by viruses, bacteria or fungi.
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- Chloropyridylcarbonyl derivatives
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Novel chloropyridylcarbonyl derivatives of the formula STR1 in which Het is STR2 n is 1 or 2, R1 is hydrogen, optionally substituted C1-6 alkyl, optionally substituted C2-6 alkenyl, optionally substituted C3-6 alkynyl, optionally substituted phenyl or optionally substituted pyrimidinyl, and R2 and R3, independently of each other, are hydrogen or C1-4 alkyl, and acid addition salts and metal salt complexes thereof, are outstandingly active as microbicides.
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- Kinetics and mechanism of oxidation of aliphatic acetals with peroxomonosulphate
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The oxidation of fifteen aliphatic acetals of normal aliphatic aldehydes and substituted aliphatic aldehydes with aliphatic and substituted aliphatic as well as with aromatic alcohols by peroxomonosulphate in aqueous acetic acid medium is first order each in [oxidant] and [acetal] and yields the corresponding esters as the main product. The oxidation reaction is independent of change in dielectric constant of the medium. The activation enthalpies and entropies of the reactions are linearly related. A mechanism involving hydride ion shift is proposed.
- Janakiram,Venkataraman,Basheer Ahamed
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p. 339 - 341
(2007/10/03)
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- Catalysis of Anilide Ethanolysis by Barium- and Strontium - Ethoxide Pairs and Their Complexes with 18-Crown-6
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The metal-bound ethoxide species that are quantitatively formed upon mixing equimolar amounts of Me4NOEt and alkaline-earth (Ba, Sr) metal salt in ethanol solution are more reactive than free ethoxide in the cleavage of simple activated amides (e.g. N-methyl-2,2,2-trifluoroacetanilide) lacking any donor group for binding to the metal ion. It is suggested that a metal-coordinated solvent molecule acts as a general acid catalyst for expulsion of the aniline leaving group in the rate-determining step. The position of the proton in the transition state is strongly dependent upon structural variations in the aniline portion, as suggested by the magnitude of kinetic solvent isotope effects. Enhanced catalysis is observed upon addition of equimolar amounts of 18-crown-6, which is tentatively interpreted on the basis of the notion that ion pairing is weakened upon cation binding to a crown ether. Important differences concerning metal ion effects in amide vs ester cleavage are pointed out and discussed on the basis of results obtained upon structural modifications of the substrates.
- Cacciapaglia, Roberta,Di Stefano, Stefano,Kelderman, Erik,Mandolini, Luigi,Spadola, Francesco
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p. 6476 - 6479
(2007/10/03)
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- Reaction of α-halo- and α,α-dihalo-β-oxoaldehydes with o- and m-phenylenediamines
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α-Halo-β-oxoaldehydes react with o- and m-phenylenediamines to give α-halo-β-oxoenamines. In the case of o-phenylenediamine, the initially formed monoenamine undergoes concurrent intramolecular cyclization to give benzimidazole and a halocarbonyl compound. α,α-Dihalo-β-oxoaldehydes react with o- and m-phenylenediamines according to the haloformic decomposition scheme involving formylation of amino groups.
- Guseinov,Klimentova,Yudina,Kol'tsova,Moskva
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p. 459 - 461
(2007/10/03)
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- Kinetics and mechanism of oxidation of aliphatic acetals with N-chlorobenzamide
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The oxidation kinetics of thirteen aliphatic acetals of normal aliphatic aldehydes and substituted aliphatic aldehydes with aliphatic and substituted aliphatic as well as with aromatic alcohols by N-chlorobenzamide (NCB) in aqueous acetic acid medium follows first order and zero order dependence in [NCB] and [acetal] respectively and yields the corresponding esters as the main product of oxidation. (H2OCl)+ has been postulated as the oxidizing species.
- Basheer Ahamed
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p. 222 - 224
(2007/10/03)
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- 2,3-,4-,5-,6-,7-,8-,9- and/or 10-substituted dibenzoxazepine compounds, pharmaceutical compositions and methods of use
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The present invention provides substituted dibenzoxazepine compounds of Formula I: STR1 wherein X is oxygen, sulfur STR2 A is --CH2 -- or STR3 E and F may be --CH, oxygen, nitrogen or sulfur, and may not be the same; G is oxygen, nitrogen or sulfur; with the proviso that when G is oxygen or sulfur, one of E or F is nitrogen, which are useful as analgesic agents for the treatment of pain, and as prostaglandin-E2 antagonists for the treatment of prostaglandin-E2 mediated diseases, pharmaceutical compositions comprising a therapeutically-effective amount of a compound of Formula I in combination with a pharmaceutically-acceptable carrier, a method for eliminating or ameliorating pain in an animal, and a method for treating prostaglandin-E2 mediated diseases in an animal, comprising administering a therapeutically-effective amount of a compound of Formula I to the animal.
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- Kinetics and mechanism of oxidation of aliphatic acetals with lead (IV) acetate
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The oxidative cleavage of aliphatic acetals of normal aliphatic aldehydes and substituted aliphatic aldehydes with aliphatic as well as aromatic alcohols with lead tetra acetate in acetic acid, aqueous acetic acid and in acetic acid-benzene medium is first order each in and and yields the corresponding esters as the main product.The rate of oxidation depends upon the dielectric constant of the medium.Stoichiometric investigations with different acetals indicated a 1:1 stoichiometry.
- Ahamed, K. A. Basheer,Nambi, K.
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p. 1104 - 1106
(2007/10/03)
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- Fluoride anion catalyzed halogen dance in polyhalomethanes
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Tetrabutylammonium fluoride catalyzes the exchange of halogens between tetrahalomethanes.The presence of small amounts of haloform is suspected to be a necessary co-catalyst.Key Words: tetrabutyl ammonium fluoride; tetrahalomethanes; halogen exchange in.
- Sasson, Y.,Kitson, F.,Webster, O, W.
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p. 599 - 600
(2007/10/02)
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- Analyse structurale des derives fonctionnels des acides carboxyliques Partie III. Acetate d'ethyle et derives α-halogenes
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Methylene bending mode analysis of ethyl esters of acetic and haloacetic acids XCH2CO2C2H5 where X=H(I), F(II), Cl(III), Br(IV) and I(V) reveals that in the dissolved state (CCl4) these compounds have conformations induced by rotating motion of the XCH2 and C2H5 groups ( (II), (III) and (IV) ) or by C2H5 group rotation exclusively ( (I) and (V) ).In the last case, (I) exists in gauche and anti conformations while (V) occurs in gauche-gauche and gauche-anti conformations.A theoretical study of compounds (I), (II) and (III) by the PCILO method and Onsager formalism leads to the following conclusions.The conformers of (I) have a dihedral angle (H3)C-C(H2)-O-C of 70 deg (gauche conformer) and 180 deg (anti conformer).For (II) and (III), there are four stable conformers whose dihedral angles φ3=(H3)C-C(H2)-O-C and θ=X-C-C=O values are in agreement with C2H5 and CH2X group orientations found in experimental analysis.
- Maury, Catherine,Petrissans, Jean
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p. 221 - 232
(2007/10/02)
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- Specific esterase activity of subtilisin toward esters of α-haloacids
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Esters of α-haloacids are specific substrates for subtilisin which catalyses their hydrolysis in aqueous media. The same esters undergo transesterifications in organic solvents in the presence of subtilisin immobilized on an alumina-phosphate complex.
- Pugniere,Juan, C. San,Previero
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p. 4883 - 4886
(2007/10/02)
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- PERFLUORINATED RESINSULFONIC ACID - A CATALYST FOR CERTAIN ORGANIC REACTIONS.
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The purpose of this work was to examine the possibility of using, as a catalyst in certain organic reactions, the perfluorinated resinsulfonic acid F-4SK in the H form, which is an analog of the perfluorinated resinsulfonic acid Nafion-H. To compare catalyst activity of the perfluorinated resinsulfonic acid in decomposition of cumene hydroperoxide, CHP was also decomposed in presence of KU-2 resin. It was found that during repeated use over a period of 150 h the activity of KU-2 catalyst under analogous conditions fell by 4-6%. During the same time the activity of the perfluorinated resinsulfonic acid remained unchanged. It is also known that the presence of a strong acid in the reaction mixture causes formation of by-products, namely the products of condensation of phenol with acetone and dimethylphenylcarbinol, and of dehydration of dimethylphenylcarbinol, with formation of alpha -methylstyrene and products of greater complexity.
- Etlis,Beshenova,Semenova,Shomina,Dreiman,Balaev
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p. 551 - 555
(2007/10/02)
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- REACTIONS OF CHLORINE MONOFLUORIDE. IV. ADDITION OF CHLORINE MONOFLUORIDE TO HALOGEN-SUBSTITUTED ALKENES
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The reactions of chlorine monofluoride with halogenoethylenes (1,1-dichloro-, 1,2-dichloro-, trichloro-, and tetrachloroethylenes) and halogenopropenes ( 3-bromo-, 3,3,3-trichloro-, E- and Z-1,3-dichloro-, 3-chloro-2-methyl-, and perfluoropropenes) were investigated in inert solvents in the presence of ethyl acetate as external nucleophile.In all cases chloroacyloxy adducts were isolated and identified in addition to the chlorofluorination products, and this indicates an electrophilic mechanism for the chlorofluorination of polyhalogenoalkenes.Methyl chloromaleate, chlorofumarate, chlorofluoroethylenedicarboxylate, α,β-difluoroacrylate, and perfluoromethacrylate in anhydrous hydrogen fluoride form the corresponding chlorofluoro adducts with satisfactory yields, whereas the reaction takes place with difficulty in inert solvents.
- Boguslavskaya, L. S.,Chuvatkin, N. N.,Panteleeva, I. Yu.
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p. 1832 - 1842
(2007/10/02)
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- Ring Cleavage Reactions of 3- and 5-Non-substituted Isoxazoles
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5-Methylisoxazoles with electron-accepting groups at C-4 (Ia-c) and 2,3-dimethylisoxazolium iodide (II) undergo ring cleavage when treated with organic bases.The nature of the open chain products which were obtained (stable enolates, β-diketones, esters) depends on the group at C-4 and the strength of the base.In some of these processes aromatic aldehydes were used in order to determine the competition between the condensation and the cleavage reaction.The mechanism of the nucleophilic ring cleavage of II is also shown.
- Alberola, A.,Gonzalez, A. M.,Guerra, D.,Pulido, F. J.
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p. 1073 - 1076
(2007/10/02)
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