- Microwave-promoted Beller's synthesis of substituted phthalates
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A rapid and efficient synthesis of substituted phthalates via microwave-promoted Beller's reaction of aldehydes, amides, and dimethyl acetylenedicarboxylate is described. This one-pot, multicomponent reaction was performed under acetic anhydride-free and solvent-free conditions. Copyright Taylor & Francis Group, LLC.
- Yang, Yun-Yun,Shou, Wang-Ge,Wang, Yan-Guang
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- Comparison of three methods for the methylation of aliphatic and aromatic compounds
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Rationale: Methylation protocols commonly call for acidic, hot conditions that are known to promote organic 1H/2H exchange in aromatic and aliphatic C–H bonds. Here we tested two such commonly used methods and compared a third that avoids these acidic conditions, to quantify isotope effects with each method and to directly determine acidic-exchange rates relevant to experimental conditions. Methods: We compared acidic and non-acidic methylation approaches catalyzed by hydrochloric acid, acetyl chloride and EDCI (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide)/DMAP (4-dimethylaminopyridine), respectively. These were applied to two analytes: phthalic acid (an aromatic) and octacosanoic acid (an aliphatic). We analyzed yield by gas chromatography/flame ionization (GC/FID) and hydrogen and carbon isotopic compositions by isotope ratio mass spectrometry (GC/IRMS). We quantified the 1H/2H exchange rate on dimethyl phthalate under acidic conditions with proton nuclear magnetic resonance (1H-NMR) measurements. Results: The δ2H and δ13C values and yield were equivalent among the three methods for methyl octacosanoate. The two acidic methods resulted in comparable yield and isotopic composition of dimethyl phthalate; however, the non-acidic method resulted in lower δ2H and δ13C values perhaps due to low yields. Concerns over acid-catalyzed 1H/2H exchange are unwarranted as the effect was trivial over a 12-h reaction time. Conclusions: We find product isolation yield and evaporation to be the main concerns in the accurate determination of isotopic composition. 1H/2H exchange reactions are too slow to cause measurable isotope fractionation over the typical duration and reaction conditions used in methylation. Thus, we are able to recommend continued use of acidic catalysts in such methylation reactions for both aliphatic and aromatic compounds.
- Lee, Hyejung,Feakins, Sarah J.,Lu, Zhiyao,Schimmelmann, Arndt,Sessions, Alex L.,Tierney, Jessica E.,Williams, Travis J.
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- Determination of Total Phthalate in Urine by Gas Chromatography
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While urine rarely contains significant quantities of phthalate diesters, it does contain a variety of metabolites (phthalate monoesters) including conjugates.In the absence of bacterial action following excretion, the metabolites retain an intact phthalate ring.A procedure for the hydrolysis of phthalate esters and metabolites to free phthalic acid, recovery and esterification of the acid, and gas chromatographic quantification of the product ester all relative to an internal standard of 4-chlorophthalate has been developed.The measurement limit is 0.5 nmol of total phthalate/mL of urine, and the relative standard deviation is approximately 1.8percent for four or more replicates.The assay is linear between 0.5 and 50 nmol/mL urine, which spans the range of phthalate levels found thus far in human urine samples.The procedure can also be used to determine levels of isophthalate and terephthalate simultaneously with phthalate.
- Albro, Phillip W.,Jordan, Sandra,Corbett, Jean T.,Schroeder, Joanna L.
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- Preparation and isolation of isobenzofuran
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The synthesis, isolation and characterization of isobenzofuran are described in this publication. Isobenzofuran is of general interest in synthetic and physical organic chemistry because it is one of the most reactive dienes known. A number of synthetic pathways have been published which all suffer from disadvantages such as low yields and difficult purification. We present a synthetic pathway to prepare isobenzofuran in laboratory scale with high yields, from affordable, commercially available starting materials.
- Peters, Morten K.,Herges, Rainer
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- Cleavage of 7- And 8-nitropyrido[1,2-a]benzimidazoles on treatment with dimethyl acetylenedicarboxylate
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7-Nitropyrido[1,2-a]benzimidazole and 8-nitropyrido[1,2-a]benzimidazole undergo cleavage-recyclization under the action of an excess of dimethyl acetylenedicarboxylate.
- Varlamov, Alexey V.,Savitkina, Elena A.,Krapivko, Anatoly P.,Chernyshev, Alexey I.,Levov, Alexander N.
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- Barrelene Derivatives-Potential Modules for Assembly
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Dihydrobarrelene tetraamide 8 was prepared by Diels-Alder reaction of 4 and 5 and indirect transformation of the ester into amide groups.The crystal structure of 8 showed an unpredicted conformation of the four amide groups.
- Beerly, Rene,Rebek, Julius
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- Carbon-Carbon Double Bond Formation Accompanying Hydride Transfer from a Carbanion to 5-Carbalumiflavin
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Oxidation of the carbanions of dimethyl trans-(1,2-2H0)dihydrophthalate and the corresponding (1,2-2H2) analogue occurs by H- and D- transfer to the 5-position of 5-carbalumiflavin.
- Farng, Oscar L.,Bruice, Thomas C.
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- The palladium-catalyzed addition of various vinyl compounds to dimethyl acetylenedicarboxylate
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The catalyst precursor (E = COOCH3) reacts with simple vinyl compounds and dimethyl acetylenedicarboxylate to give cyclic 1:2-, 2:1- and 2:2-addition products, namely substituted cyclohexadiene or benzene, cyclopentene and cyclooctadiene derivatives, which can be separated by column chromatography.Palladacyclopent-2-enes, palladacyclohepta-2,4-dienes and palladacyclohept-4-enes, which cannot be trapped, are suggested to be intermediates in the reaction.Different types of products are obtained depending on the nature of the vinyl compound: while α-methyl styrene gives only a cyclohexadiene species following 1:2-addition, vinyl ethers along with 1:2-addition undergo 2:1- and even 2:2-addtition, and cyclopentene and 1,5-cyclooctadiene derivatives are formed.In the course of the reaction with vinyl ethers, alcohols are formed, probably in a reductive elimination step from Pd-H-intermediates in which an alkoxy group occupies a β-position and also in palladium-mediated aromatization of initially formed alkoxy cyclohexadiene and bisalkoxy cyclohexene products.Yields and product ratios can be influence by changing the fixed ligand in the catalyst complex.
- Stephan, Constantin,Munz, Christina,Dieck, Heindirk tom
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- Arene synthesis by extrusion reaction X. Synthesis of arenes by deoxygenation of endoxides with cyclopentadienyltitanium trichloride/lithium aluminum hydride and dicyclopentadienyltitanium dichloride/lithium aluminum hydride
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The two homogeneous systems, cyclopentadienyltitanium trichloride/lithium aluminum hydride and dicyclopentadienyltitanium dichloride/lithium aluminum hydride have been utilized to deoxygenate 1,4-endoxides in tetrahydrofuran.The results show that they can provide corresponding arenes in fair yields.
- Wong, Chi Hung,Hung, Chi Wai,Wong, Henry N. C.
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- Reactions of 2,3-dicarbomethoxy-7-oxabicycloheptadiene with molybdenum carbonyls
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Thermolysis with either Mo(CO)6 or Mo(CH3CN)3(CO)3 of 2,3-dicarbomethoxy-7-oxabicycloheptadiene (I) gave three major products, i.e. dimethyl phthalate (V), 3,4-dicarbomethoxyfuran (VI), and a dimeric ketone (IX) linked in an exo-trans-exo orientation.The formation of V and IX indicates two reaction pathways which start from a common organometallic intermediate.Compound VI is the major product in the thermal decomposition of IX.
- Sun, Chia-Hsing,Chow, Tahsin J.
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- A cyclobutadiene equivalent in the catalytic Pauson-Khand reaction
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A practical and scalable operation: The reaction shown in the scheme, which uses catalytic amounts of hexacarbonyldicobalt, gives access to versatile bicyclic systems, which until now could only be obtained in low quantities by a photochemical process starting from tropolones. An isolation of the primary Pauson-Khand products is not necessary.
- Gibson, Susan E.,Mainolfi, Nello,Kalindjian, S. Barret,Wright, Paul T.
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- Preparation of phthalates via carbonylation of o-dibromobenzenes in solutions of Pd catalysts and reactivity of Ar?Br bonds
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Carbonylation of o-dibromobenzene and its derivatives in the presence of palladium phosphine complexes with NaOAc or Et3N additive leads to the formation of phthalates in high yield under mild conditions. Correlation NMR spectroscopy data and s
- Elman,Perepukhov,Ovsyannikova,Maksimychev
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- Ortho-disubstitution reactions of aromatic rings with homo-conjugated bicyclo[2.2.2]octa-2,5-diene derivatives in the presence of palladium(II) acetate
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Bicyclo[2.2.2]octa-2,5-diene derivatives 5 and 7 reacted with aromatic compounds such as benzene, naphthalene, anthracene, phenanthrene, and tropone in the presence of Pd(OAc)2 to afford ortho-disubstituted aromatics 6 and 8-12. Since the yields and regioselectivity were generally low, the reaction conditions were optimized by using iodoarenes as reagents to provide sufficient yields and regioselectivity. In order to investigate reactivities of diene moieties, several kinds of homo-conjugated dienes were surveyed for the reaction. Only dienes containing a bicyclo[2.2.2]octa-2,5-diene skeleton gave the ortho-disubstituted aromatics.
- Saito, Katsuhiro,Ono, Katsuhiko,Takeda, Toshifumi,Kiso, Shingo,Uenishi, Kazuya,Kozaki, Masatoshi
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- Insertion of rhodium into the carbon-sulfur bond of thiophene. Mechanism of a model for the hydrodesulfurization reaction
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The reaction of (C5Me5)Rh(PMe3)(Ph)H with thiophene leads to the elimination of benzene and oxidative addition of the thiophene C-S bond across the Rh(I) center, giving (C5Me5)Rh(PMe3)(SCH=CHCH=CH). Similar reactions occur with 2-methylthiophene, 3-methylthiophene, 2,5-dimethylthiophene, benzothiophene, and dibenzothiophene. Selectivity studies performed with these complexes are consistent with the coordination of sulfur to rhodium prior to C-S bond cleavage. Reversible reductive elimination of thiophene occurs at ~80°C. The diene portion of the C-S insertion ligand undergoes a Diels-Alder reaction with dimethyl acetylenedicarboxylate to give dimethyl phthalate as a major product. The dimethylthiophene complex (C5Me5)Rh(PMe3)(SCMe=CHCH=CMe) was structurally characterized, crystallizing in the monoclinic space group P1 with a = 8.707 (8) A?, b = 14.157 (15) A?, c = 8.637 (5) A?, α = 100.90 (8)°, β = 106.07 (6)°, γ = 87.85 (8)°, V = 1004 (3) A?3, and Z = 2.
- Jones, William D.,Dong, Lingzhen
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- Identification of the Tricarbonyliron Complex of 7-Azabicycloheptadiene Derivatives as the Intermediate in Nitrene Extrusion Reactions
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Several tricarbonyliron complexes of N-substituted 7-aza-2,3-bismethoxycarbonylbicycloheptadiene have been isolated and identified as the intermediates of nitrene-extrusion reactions.
- Sun, Chia-Hsing,Chow, Tahsin J.
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- Mechanistic Insights on Pd/Cu-Catalyzed Dehydrogenative Coupling of Dimethyl Phthalate
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Despite its industrial importance, very limited mechanistic information on the dehydrogenative coupling of dimethyl phthalate has been reported. Herein we report the detailed mechanism for dehydrogenative coupling of dimethyl phthalate catalyzed by [Pd(OAc)2]/[Cu(OAc)2]/1,10-phenanthroline·H2O (phen·H2O). The solution-phase analysis of the catalytic system by XANES shows the active species to be Pd(II), and EXAFS supports the formation of an (acetato)(dimethyl phthalyl)(phen)palladium(II) complex from [Pd(OAc)2]. A formation pathway of tetramethyl 3,3′,4,4′-biphenyltetracarboxylate via disproportionation of independently prepared [Pd(OAc){C6H3(CO2Me)2-3,4}(phen)] is observed with regeneration of [Pd(OAc)2(phen)].
- Hirano, Masafumi,Sano, Kosuke,Kanazawa, Yuki,Komine, Nobuyuki,Maeno, Zen,Mitsudome, Takato,Takaya, Hikaru
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- Thermally-induced Reorganization of -Ladderanes
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Thermolysis of -, - and -ladderane derivatives has unravelled some novel, deep-seated rearrangements of these fascinating molecular arrays.
- Mehta, Goverdhan,Viswanath, M. Balaji,Kunwar, Ajit C.,Kumar, K. Ravi,Reddy, D. Siva Kumar
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- Synthesis and flash vacuum pyrolysis of dimethyl anti-7-nitro-2,5-norbornadiene-2,3-dicarboxylate
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Reaction of dimethyl anti-7-(trimethylsilyl)-2,5-norbornadiene-2,3-dicarboxylate (dimethyl anti-7-(trimethylsilyl)bicyclo[2.2.1]hepta-2,5-diene- 2,3-dicarboxylate, 1) with nitronium tetrafluoroborate affords the title compound 2 (65%). Subsequent photolysis of 2 affords the corresponding substituted quadricyclane derivative 3 (75%). Flash vacuum pyrolysis of 2 at 600°C affords dimethyl phthalate (67%) as the only isolable product.
- Marchand,Reddy,Dave
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- A Convenient Synthesis of 7-Substituted Norbornadienes
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7-Substituted norbornadienes were conveniently synthesized from the adduct of nickelocene and dimethyl acetylenedicarboxylate
- Luh, Tien-Yau,Lung, Ching Leung
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- Nickel-Catalyzed Carboxylation of Aryl C?F Bonds with CO2
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The C?F bond is the strongest single bond and it is one of the most challenging tasks to achieve the C?F bond functionalization. Here, we describe the first nickel-catalyzed selective defluorinative carboxylation of aryl C?F bonds with CO2. Var
- Pei, Chunzhe,Wang, Baiquan
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p. 1245 - 1250
(2022/03/18)
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- Electrochemical esterification via oxidative coupling of aldehydes and alcohols
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An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
- Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
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supporting information
(2021/03/26)
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- Method for coproducing methyl benzoic acid Process for the production of methyl benzoates and diesters of phthalic acids
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The invention discloses a coproduction method of methylbenzoic acid, methyl benzoate and benzenedicarboxylic acid diester. The method comprises the following steps: (1) continuously introducing xylene, a catalyst and oxygen-containing gas into an oxidation reactor for a reaction, and controlling oxygenic concentration in the tail gas to not exceed 5% by controlling introduction amount of the oxygen-containing gas to obtain an oxidation reaction liquid; (2) feeding the obtained oxidation reaction liquid into a predistillation tower for distillation separation to obtain a low-boiling-point component and a predistillation tower bottom liquid; (3) feeding the predistillation tower bottom liquid into a distillation tower for distillation to obtain a methylbenzoic acid product and a distillationtower bottom liquid; (4) mixing the distillation tower bottom liquid and alcohol for an esterification reaction, and controlling the reaction endpoint to be lower than 0.5wt% of the content of methylbenzoic acid to obtain an esterification reaction liquid; (5) performing distillation separation on the obtained esterification reaction liquid to obtain methyl benzoate and benzenedicarboxylic acid diester products. The method has the advantages that the process is simple, equipment investment is low, and the method is environmentally friendly and has good comprehensive economic benefits.
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Paragraph 0176-0192
(2021/02/09)
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- Ultralow-Molecular-Weight Stimuli-Responsive and Multifunctional Supramolecular Gels Based on Monomers and Trimers of Hydrazides
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The simpler, the better. A series of simple, neutral and ultralow-molecular-weight (MW: 140–200) hydrazide-derived supramolecular gelators have been designed and synthesized in two straightforward steps. For non-conjugated cyclohexane-derived hydrazides, their monomers can self-assemble to form gels through intermolecular hydrogen bonds and dipole-dipole interactions. Significantly, conjugated phthalhydrazide can self-aggregate into planar and circular trimers through intermolecular hydrogen bonds and then self-assemble to form gels through intermolecular π–π stacking interactions. It is interesting that these simple gelators exhibit unusual properties, such as self-healing, multi-response fluorescence, and visual and selective recognition of chiral (R)/(S)-1,1′-binaphthalene-2,2′-diamine and S2? through much different times of gel re-formation and blue-green color change, respectively. These results underline the importance of supramolecular gels and extend the scope of supramolecular gelators.
- Wu, Dehua,Song, Jintong,Qu, Lang,Zhou, Weilan,Wang, Lei,Zhou, Xiangge,Xiang, Haifeng
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supporting information
p. 3370 - 3378
(2020/10/02)
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- Cobalt Nanoparticles-Catalyzed Widely Applicable Successive C?C Bond Cleavage in Alcohols to Access Esters
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Selective cleavage and functionalization of C?C bonds have important applications in organic synthesis and biomass utilization. However, functionalization of C?C bonds by controlled cleavage remains difficult and challenging because they are inert. Herein, we describe an unprecedented efficient protocol for the breaking of successive C?C bonds in alcohols to form esters with one or multiple carbon atoms less using heterogeneous cobalt nanoparticles as catalyst with dioxygen as the oxidant. A wide range of alcohols including inactive long-chain alkyl aryl alcohols undergo smoothly successive cleavage of adjacent ?(C?C)n? bonds to afford the corresponding esters. The catalyst was used for seven times without any decrease in activity. Characterization and control experiments disclose that cobalt nanoparticles are responsible for the successive cleavage of C?C bonds to achieve excellent catalytic activity, while the presence of Co-Nx has just the opposite effect. Preliminary mechanistic studies reveal that a tandem sequence reaction is involved in this process.
- Dai, Wen,Gao, Shuang,Li, Guosong,Luo, Huihui,Lv, Ying,Shang, Sensen,Wang, Lianyue
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supporting information
p. 19268 - 19274
(2020/08/26)
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- Regioselective arene homologation through rhenium-catalyzed deoxygenative aromatization of 7-oxabicyclo[2.2.1]hepta-2,5-dienes
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Combined use of oxorhenium catalysts with triphenyl phosphite as an oxygen acceptor allowed efficient deoxygenative aromatization of oxabicyclic dienes. The reaction proceeded under neutral conditions and was compatible with various functional groups. Combining this deoxygenation with regioselective bromination and trapping of the generated aryne with furan resulted in benzannulative π-extension at the periphery of the PAHs. This enabled direct use of unfunctionalized PAHs for extension of π-conjugation. Iteration of the transformations increased the number of fused-benzene rings one at a time, which has the potential to alter the properties of PAHs by fine-tuning the degree of π-conjugation, shape, and edge topology.
- Murai, Masahito,Ogita, Takuya,Takai, Kazuhiko
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supporting information
p. 2332 - 2335
(2019/02/27)
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- Efficient and Recyclable RuCl3 ? 3H2O Catalyst Modified with Ionic Diphosphine for the Alkoxycarbonylation of Aryl Halides
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A series of ionic (mono-/di-)phosphines (L2, L4, and L6) with structural similarity and their corresponding neutral counterparts (L1, L3, and L5) were applied to modulate the catalytic performance of RuCl3 ? 3H2O. With the involvement of the ionic diphosphine (L4), in which the two phosphino-fragments were linked by butylene group, RuCl3 ? 3H2O with advantages of low cost, robustness, and good availability was found to be an efficient and recyclable catalyst for the alkoxycarbonylation of aryl halides. The L4-based RuCl3 ? 3H2O system corresponded to the best conversion of PhI (96 %) along with 99 % selectivity to the target product of methyl benzoate as well as the good generality to alkoxycarbonylation of different aryl halides (ArX, X=I and Br) with alcohols MeOH, EtOH, i-PrOH and n-BuOH. The electronic and steric effects of the applied phosphines, which were analyzed by the 31P NMR for 1J31P-77Se1J measurement and single-crystal X-ray diffraction, were carefully co-related to the performance RuCl3 ? 3H2O catalyst. In addition, the L4-based RuCl3 ? 3H2O system could be recycled successfully for at least eight runs in the ionic liquid [Bmim]PF6.
- Zhou, Qing,Liu, Lei,Guo, Wen-Di,Liang, Wen-Yu,Lu, Yong,Liu, Ye
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p. 166 - 172
(2019/02/01)
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- Methylation of Aliphatic and Aromatic Carboxylic Acids with Dimethyl Carbonate under the Influence of Manganese and Iron Carbonyls
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The synthesis of methyl esters has been carried out via the reaction of aliphatic and aromatic carboxylic acids with dimethyl carbonate in the presence of manganese and iron carbonyls. The optimal ratio of catalyst and reagents and other conditions for the synthesis of methyl esters of carboxylic acids with high yield have been found.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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- Diacidic ionic liquid supported on magnetic-silica nanocomposite: a novel, stable, and reusable catalyst for selective diester production
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Abstract: Supported diacidic ionic liquid on magnetic silica nanoparticles (SDAIL@magnetic nanoSiO2) was successfully prepared through a multi-step approach. 2,2- bis ((3- methylimidazolidin-1-yl) methyl) propane- 1,3- diol bromide salt was immobilized onto the surface of magnetic silica nanoparticles via covalent bonding to prepare a novel powerful acidic catalyst. The synthesized catalyst was characterized by FT-IR, SEM, TGA, VSM, N2 adsorption–desorption measurements and acid-base titration. The catalytic activity of the prepared SDAIL@magnetic nanoSiO2 was investigated for the selective diesterification of alcohols by phthalic anhydride to afford corresponding dialkyl plasticizers under solvent-free conditions. The nature of two acidic counter anions as well as the presence of Lewis acidic species (Fe3O4) on the magnetic nanosilica and high surface area of the nanosilica influenced the behavior of the catalyst. Surperisingly, the high acidic character of the catalyst facilitates the reaction with a short reaction time. Furthermore, TG analysis strongly demonstrates that major content of IL is still stable on the support up to 290?°C, so catalyst has a good thermal stability. Under the optimized conditions, the conversion of phthalic anhydride was 100% and diester plasticizers were obtained with excellent yields (80–100%). The SDAIL@magnetic nanoSiO2 catalyst showed a good reusability and could be easily separated from the reaction mixture using an external magnet thanks to its superparamagnetic behavior and reused for several runs without significant activity loss. An important advantage of the SDAIL@magnetic nanoSiO2 was its high-hydrophilicity resulted in excellent selectivity towards the formation of only diesters which are commonly used plasticizers in different industries. Graphical abstract [Figure not available: see fulltext.].
- Fareghi-Alamdari, Reza,Nadiri Niri, Mehri,Hazarkhani, Hassan,Zekri, Negar
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p. 2615 - 2629
(2018/09/13)
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- A novel hydrogen-bonded silica-supported acidic ionic liquid: An efficient, recyclable and selective heterogeneous catalyst for the synthesis of diesters
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Abstract: In this study, two novel acidic ionic liquids, including a hydroxyl functionalized diacidic ionic liquid [HFDAIL] and a sulfonated diacidic ionic liquid [SFDAIL], were prepared and immobilized on the surface of silica nanoparticles (SNPs) via hydrogen bonding. The materials were characterized by FT-IR, NMR, SEM, nitrogen physisorption measurement, TGA and acid-base titration. The catalytic activity of the prepared catalysts was investigated in the synthesis of phthalate, maleate and succinate diesters under solvent-free conditions. It was found that nanosilica@[HFDAIL] with higher availability of acidic sites and higher hydrophilicity was more efficient compared to the nanosilica@[SFDAIL]. Notably, nanosilica@[HFDAIL] catalyst has also demonstrated excellent selectivity for the diester product while the monoester product was predominant in the case of nanosilica@[SFDAIL] even after prolonged reaction time or higher catalyst loading. In addition, the nanosilica@[HFDAIL] catalyst could be separated by simple filtration and reused several times without any significant loss of catalytic performance, but a remarkable decrease in activity was observed for nanosilica@[SFDAIL] in the next runs. GRAPHICAL ABSTRACT?: SYNOPSIS Two novel acidic ionic liquids, including a hydroxyl functionalized diacidic ionic liquid [HFDAIL] and a sulfonated diacidic ionic liquid [SFDAIL], were prepared and immobilized on the surface of silica nanoparticles via hydrogen bonding. The catalytic activity of the catalysts was investigated in the synthesis of diesters under solvent-free conditions.
- Fareghi-Alamdari, Reza,Niri, Mehri Nadiri,Hazarkhani, Hassan
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- Silica supported polynuclear sulfonate acidic ionic liquid and application
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The invention relates to silica supported polynuclear sulfonate acidic ionic liquid and a method for preparing dimethyl phthalate by utilizing the silica supported polynuclear sulfonate acidic ionic liquid. The silica supported polynuclear sulfonate acidic ionic liquid is prepared by performing silica supporting on polynuclear sulfonate acidic ionic liquid shown in a formula (I). According to thecatalyst in the invention, the problems existing in the conventional acid catalyst that follow-up treatment is complicated, equipment corrosion is severe, lots of industrial wastewater is discharged and the like can be solved. Moreover, the catalyst has excellent heat-resistant stability and high-efficiency catalytic activity (an esterification rate can reach 96-99%) in a reaction of preparing thedimethyl phthalate, is easily separated from the product, can be repeatedly used, and is simple in recovery operation, long in life and mild in reaction conditions, pollution of the acid catalyst tothe environment and corrosion of the catalyst on equipment can be overcome, the production process is simplified, and the production cost is saved. The structural formula is as shown in the description.
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Paragraph 0045-0066
(2018/10/19)
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- Method for synthesizing aromatic acid ester
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The invention relates to a method for synthesizing aromatic acid ester. Corresponding aromatic acid ester is synthesized from aromatic acid and lower carbon alcohol used as raw materials with a catalytic esterification means through an esterification reaction performed by efficiently catalyzing aromatic acid and lower carbon alcohol with a solid acid catalyst with the surface modified with a sulfonic acid group and immobilized with an imidazole acid ionic liquid at a certain temperature. The catalytic reaction operation is simple, the selectivity of the aromatic ester product can reach 99% or above when aromatic acid is completely converted, and the catalyst has good hydrothermal stability and reusability.
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Paragraph 0023; 0024; 0034; 0042
(2017/09/05)
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- Methylation of mono- and dicarboxylic acids with dimethyl carbonate catalyzed with binder-free zeolite NaY
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Synthesis of methyl mono- and dicarboxylates was developed consisting in treating the corresponding acids with dimethyl carbonate in the presence of a heterogenic catalyst, crystalline aluminosilicate whose mechanically strong granules to 90–95% were built of crystal aggregates of zeolite Y with modulus of about 5.0 in the Na-form. Optimum catalyst and reagents ratio and the reaction conditions were found for the preparation in high yields of methyl esters of mono- and dicarboxylic acids.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.,Konovalova, Yu. S.,Khazipova,Kutepov
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p. 163 - 168
(2017/04/24)
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- Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
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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
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supporting information
p. 5033 - 5040
(2017/07/10)
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- Synthesis and characterization of a new hydroxyl functionalized diacidic ionic liquid as catalyst for the preparation of diester plasticizers
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Two new functionalized diacidic ionic liquids (FDAILs) including hydroxyl functionalized diacidic ionic liquid (HFDAIL) and sulfonated diacidic ionic liquid (SFDAIL) were synthesized and characterized by 1HNMR, 13CNMR and FT-IR. The catalytic activities of these FDAILs were examined in esterification reaction of anhydrides with some alcohols to give corresponding dialkyl plasticizers under solvent-free conditions. The results indicate that HFDAIL, as hydroxyl-bearing catalyst, show better catalytic performance. Under the optimum conditions, using HFDAIL, the conversion of phthalic anhydride was high and diester plasticizers were obtained with good to excellent yields in the presence of only 10?mol% of ionic liquid. All the produced diesters could be easily recovered due to their immiscibility with the ionic liquid. Recycling experiments suggests that these ionic liquids can be reused several times without remarkable loss in their catalytic activity.
- Fareghi-Alamdari, Reza,Nadiri Niri, Mehri,Hazarkhani, Hassan
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p. 153 - 160
(2016/12/30)
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- Method for synthesizing carboxylic methyl ether by reaction between acid anhydrides and dimethyl carbonate
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The invention discloses a method for synthesizing carboxylic methyl ether by a reaction between acid anhydrides and dimethyl carbonate. The method is characterized by comprising the following steps: taking raw materials acid anhydride, dimethyl carbonate and a catalyst, wherein molar ratio of acid anhydride to dimethyl carbonate is 1:1-1:100, the catalyst accounts for 1-20 wt% of mass of acid anhydride, acid anhydride is aliphatic acid anhydride or aromatic acid anhydride, and the catalyst is Lewis acid or protonic acid; adding acid anhydride, dimethyl carbonate and the catalyst into a high-pressure reaction vessel, reacting at 80-350 DEG C for 1-8h, cooling to room temperature, discharging gas, and fetching a material obtained after the reaction; pouring the material into a saturated sodium bicarbonate aqueous solution, extracting with ethyl acetate or dichloromethane, merging extract liquor, drying, filtering, and distilling a filtrate to remove a solvent. The remaining product is prepared carboxylic methyl ether. By the method, no additional organic solvent is required. The method is green and environment-friendly, is simple to operate, has short reaction time, has high acid anhydride conversion rate, and has a good application prospect.
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Paragraph 0017
(2017/08/28)
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- Metal-free radical aromatic carbonylations mediated by weak bases
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We report a new method of metal-free alkoxycarbonylation. This reaction involves the generation of aryl radicals from arenediazonium salts by a very weak base (HCO2Na) under mild conditions. Subsequent radical trapping with carbon monoxide and alcohols gives alkyl benzoates. The conditions (metal-free, 1 equiv. base, MeCN, r.t., 3 h) tolerate various functional groups (I, Br, Cl, CF3, SF5, NO2, ester). Mechanistic studies indicate the operation of a radical aromatic substitution mechanism.
- Koziakov, Denis,Jacobi Von Wangelin, Axel
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supporting information
p. 6715 - 6719
(2017/08/22)
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- A Ni-Mg-Al layered triple hydroxide-supported Pd catalyst for heterogeneous acceptorless dehydrogenative aromatization
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In the presence of a Ni-Mg-Al layered triple hydroxide-supported Pd catalyst, the acceptorless dehydrogenative aromatization of a wide range of cyclohexanols/cyclohexanones and cyclohexylamines efficiently proceeded to give the corresponding phenols and anilines, respectively, in moderate to high yields with the liberation of molecular hydrogen.
- Jin, Xiongjie,Taniguchi, Kento,Yamaguchi, Kazuya,Nozaki, Kyoko,Mizuno, Noritaka
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supporting information
p. 5267 - 5270
(2017/07/10)
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- Method for producing aromatic acid esters through catalytic distillation
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The invention discloses a method for producing aromatic acid esters through catalytic distillation. According to the method, aromatic acid and low-carbon alcohol are used as raw materials, and a course of generating the aromatic acid esters and a course of separating and distilling products through a reaction in a catalytic distillation tower are performed at the same time, so that a technological process is simplified. According to the technique of the method disclosed by the invention, a manner of extracting aromatic ester products from the middle part of a distillation segment is adopted, and aromatic ester products with high purity are directly obtained. The method is high in universality, and is suitable for preparing aromatic acid including benzoic acid, phthalic acid, methyl benzoic acid and the like into high-purity aromatic esters. Compared with a conventional aromatic acid ester preparing technique, the method disclosed by the invention has the advantages of being simple in flow, few in by-products, low in operating cost, light in product color, high in product purity and the like.
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Paragraph 0021; 0022
(2017/06/13)
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- A liquid phase oxidation of O-xylene with esterification coupling preparation of phthalic acid diester method
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The invention relates to a method for preparation of diester phthalate by o-xylene liquid-phase oxidation and esterification coupling. In the presence of a catalyst, air or oxygen is used as an oxygen source for preparation of the diester phthalate by o-xylene liquid-phase oxidation and esterification coupling. The method has the advantages of mild reaction conditions, safe operation, low raw material and energy consumption, high conversion rate and high selectivity and the like.
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Paragraph 0020-0023; 0025
(2017/02/24)
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- Palladium-Catalyzed Aerobic Oxidative Dehydrogenation of Cyclohexenes to Substituted Arene Derivatives
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A palladium(II) catalyst system has been identified for aerobic dehydrogenation of substituted cyclohexenes to the corresponding arene derivatives. Use of sodium anthraquinone-2-sulfonate (AMS) as a cocatalyst enhances the product yields. A wide range of functional groups are tolerated in the reactions, and the scope and limitations of the method are described. The catalytic dehydrogenation of cyclohexenes is showcased in an efficient route to a phthalimide-based TRPA1 activity modulator.
- Iosub, Andrei V.,Stahl, Shannon S.
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supporting information
p. 3454 - 3457
(2015/03/30)
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- Sulfonated graphene as highly efficient and reusable acid carbocatalyst for the synthesis of ester plasticizers
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Plasticizers are well known for their effectiveness in producing flexible plastics. The automotive, plastic and pharmaceutical industries, essential to a healthy economy, rely heavily on plasticizers to produce everything from construction materials to medical devices, cosmetics, children toys, food wraps, adhesives, paints, and 'wonder drugs'. Although H2SO4 is commonly used as commodity catalyst for plasticizer synthesis it is energy-inefficient, non-recyclable, and requires tedious separation from the homogeneous reaction mixture resulting in abundant non-recyclable acid waste. In this study, for the first time, we report an efficient synthesis of ester plasticizers (>90% yields) using sulfonated graphene (GSO3H) as an energy-efficient, water tolerant, reusable and highly active solid acid carbocatalyst. The hydrothermal sulfonation of reduced graphene oxide with fuming H2SO4 at 120°C for 3 days afforded GSO3H with remarkable acid activity as demonstrated by 31P magic-angle spinning (MAS) NMR spectroscopy. The superior catalytic performance of GSO3H over traditional homogeneous acids, Amberlyst-15, and acidic ionic liquids has been attributed to the presence of highly acidic and stable sulfonic acid groups within the two dimensional graphene domain, which synergistically work for high mass transfer in the reaction. Furthermore, the preliminary experimental results indicate that GSO3H is quite effective as a catalyst in the esterification of oleic and salicylic acid and thus may pave the way for its broad industrial applications in the near future.
- Garg, Bhaskar,Bisht, Tanuja,Ling, Yong-Chien
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p. 57297 - 57307
(2015/02/02)
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- Copper-catalyzed decarboxylative methylation of aromatic carboxylic acids with PhI(OAc)2
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The copper-catalyzed decarboxylative methylation of aromatic carboxylic acids was developed by using PhI(OAc)2 to provide a new strategy for the methylation of aryl acids through the decarboxylation of alkyl acids. The mechanism and the roles of each reactant in the reaction were investigated extensively. Copyright
- Jiang, Yuyu,Pan, Shulei,Zhang, Yanghui,Yu, Jingxun,Liu, Hongqiang
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supporting information
p. 2027 - 2031
(2014/04/17)
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- Copper-catalyzed methyl esterification of aromatic aldehydes and benzoic alcohols by TBHP as both oxidant and methyl source
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A copper-catalyzed synthesis of methyl esters from aromatic aldehydes in the presence of tert-butyl hydrogen peroxide (TBHP) was developed via a radical reaction mechanism. TBHP acts not only as an efficient oxidant, but also as a green methyl source in such transformation. Moreover, this method could also be efficiently extended to the methyl esterification of benzylic alcohols.
- Li, Pan,Zhao, Jingjing,Lang, Rui,Xia, Chungu,Li, Fuwei
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supporting information
p. 390 - 393
(2014/01/06)
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- METHOD FOR CONTINUOUSLY PREPARING CARBOXYLIC ACID ESTER
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A method for continuously preparing a carboxylic acid ester is disclosed. In the method of the present invention, a vertical reactor is filled with a solid catalyst, a carboxylic acid and an alcohol are introduced into a lower part of the vertical reactor, esterification is performed to form an esterized mixture, the esterized mixture is output from an upper part of the vertical reactor, and distillation is performed to isolate the carboxylic acid ester. The method of the present invention is simple, easily controlled and environmental friendly, and has significantly high conversion rate and selectivity.
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Paragraph 0034
(2013/11/19)
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- Nickel-catalyzed reductive allylation of aryl bromides with allylic acetates
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This paper highlights Ni-catalyzed allylation of electron-rich aryl bromides with a variety of substituted allylic carbonates using zinc as the terminal reductant, affording E-alkenes regioselectively in good to excellent yields by the addition of aryl to the less hindered allylic carbon. The electron-deficient aryl bromides and chlorides are also highly efficient coupling partners. The Royal Society of Chemistry 2013.
- Cui, Xiaozhan,Wang, Shulin,Zhang, Yuwei,Deng, Wei,Qian, Qun,Gong, Hegui
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supporting information
p. 3094 - 3097
(2013/05/23)
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- A convenient procedure for bis-esterification of cyclic anhydrides
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Aromatic and aliphatic cyclic anhydrides are chemoselectively and conveniently transformed to the corresponding diesters by the use of DBU and appropriate alkyl/allyl halides. This bis-esterification reaction has been exemplified mostly with dimethyl esters. But in some cases, mixed dialkyl esters are also prepared.
- Jana, Amit Kumar,Karmakar, Raju,Dinda, Bidyut Kumar,Mitra, Prithiba,Ghosh, Ketaki,Karmakar, Rajdip,Mal, Dipakranjan
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p. 975 - 979
(2012/10/29)
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- Indolizinones as synthetic scaffolds: Fundamental reactivity and the relay of stereochemical information
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Indolizinones are under-explored N-heterocycles that react with exquisite chemo- and stereoselectivity. An exploration of the fundamental reactivity of these azabicycles demonstrates the potential to relay stereochemical information from the ring-fusion to newly formed stereocenters on the bicyclic core. The indolizinone diene undergoes selective hydrogenation and readily participates in Diels-Alder cycloadditions as well as ene reactions. The vinylogous amide embedded in the five-membered ring is resistant to reaction when the diene is in place. However, removal of the diene allows for diastereoselective hydrogenation of, and 1,4-additions to, the vinylogous amide. These fundamental reactions with indolizinones have provided a structurally diverse array of products that hold promise in the context of natural product synthesis.
- Hardin Narayan, Alison R.,Sarpong, Richmond
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scheme or table
p. 70 - 78
(2012/01/04)
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- Polymer-mounted N3=P(MeNCH2CH2) 3N: A green, efficient and recyclable catalyst for room-temperature transesterifications and amidations of unactivated esters
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Merrifield resin-supported N3P(MeNCH2CH 2)3N shows excellent activity in the transesterification of higher esters such as glyceryl tribenzoate to methyl esters. The catalyst was successfully cycled 20 times (albeit with an increase in reaction time) without compromising yield up to the 20th cycle. The catalyst also showed good performance in amidation reactions of unactivated esters with amino alcohols.
- Chintareddy, Venkat Reddy,Ho, Hung-An,Sadow, Aaron D.,Verkade, John G.
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experimental part
p. 6523 - 6529
(2011/12/21)
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- One-pot esterification and Ritter reaction: Chemo- and regioselectivity from tert-butyl methyl ether
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tert-Butyl methyl ether (TBME) has been effectively used as a reagent for esterification of carboxylic acids. By varying amounts of sulfuric acid, a remarkable regioselectivity in esterification has been demonstrated. Additionally, under the present reaction conditions, one-pot esterification and Ritter reaction are achieved in almost quantitative yield.
- Dawar, Pankaj,Bhagavan Raju,Ramakrishna, Ramesha A.
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supporting information; experimental part
p. 4262 - 4265
(2011/08/21)
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- Photolysis of methyl-parathion thin films: Products, kinetics and quantum yields under different atmospheric conditions
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The present study focuses on the photodegradation of methyl-parathion thin films, an organophosphate insecticide, under different atmospheric conditions. The latter include nitrogenated, oxygenated and ozonated atmospheres, under low and high relative humidity conditions. Addition of oxygen to the atmospheric mixture did not seem to affect the reaction rates and quantum yields. Relative humidity affect was minor, with a small enhancement in reaction rate under 254. nm radiation. The addition of ozone (to either dry or humid atmosphere), at all concentrations tested, largely enhanced degradation rates. In the absence of ozone, the obtained quantum yields for photolysis of methyl-parathion thin films under 254 and 313. nm were 0.024 ± 0.007 and 0.012 ± 0.005, respectively. These values are higher than the values previously reported for solutions of methanol and water. Although the presence of molecular oxygen and water vapors did not seem to affect much the reaction rates, it did have a certain effect on the resulted products. More polar products were obtained under oxygenated and ozonated atmospheres, as well as dimers under ozone conditions. The reaction on thin films has yielded more toxic products than usually found in solutions, adding alkylphosphate esters in addition to the oxons formed normally.
- Segal-Rosenheimer, Michal,Dubowski, Yael
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scheme or table
p. 193 - 202
(2010/10/01)
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- Trans-chelating ligands in palladium-catalyzed carbonylative coupling and methoxycarbonylation of aryl halides
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The manuscript describes the use of a trans-chelated palladium complex derived from 1,8-bis-(4-(diphenylphosphino)phenyl)anthracene (1) and p-TolPdI(TMEDA) as a precatalyst in carbonylative Suzuki coupling and methoxycarbonylation of aryl iodides and bromides. The catalyst is active in 0.01-1 mol% loading and demonstrates highly selective transformations. The selectivity is attributed to the unique structural features of the trans-chelating ligands.
- Kaganovsky, Luba,Gelman, Dmitri,Rueck-Braun, Karola
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experimental part
p. 260 - 266
(2010/03/26)
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- Selective oxidation of acetophenones bearing various functional groups to benzoic acid derivatives with molecular oxygen
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Acetophenones substituted by alkyl, alkoxy, acetoxy, and halogen groups were selectively oxidized with molecular oxygen to the corresponding benzoic acids by using the N,N',N"-trihydroxyisocyanuric acid (THICA)/cobalt(II) acetate [Co(OAc)2] and THICA/Co(OAc)2/manganese(II) acetate.
- Nakamura, Ryota,Obora, Yasushi,Ishii, Yasutaka
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experimental part
p. 1677 - 1684
(2011/02/25)
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- A Simple, efficient, green, cost effective and chemoselective process for the esterification of carboxylic acids
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Carboxylic acids have been esterified under mild and solvent-free conditions in high yield and purity using the green reagents, dimethyl carbonate and diethyl carbonate, under acid catalysis. The present methodology is free of the disadvantages of base catalysis described earlier, such as high temperatures, use of autoclaves, use of the expensive DBU as base in stoichiometric amounts and the carbonate as solvent. High chemoselectivity is observed in the case of hydroxybenzoic acids.
- Rekha,Ramani, Modukuri V.,Ratnamala,Rupakalpana, Vempati,Subbaraju, Gottumukkala V.,Satyanarayana, Chava,Rao, C. Someswara
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experimental part
p. 769 - 773
(2010/04/22)
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- NOVEL FORMULATION OF DEHYDRATED LIPID VESICLES FOR CONTROLLED RELEASE OF ACTIVE PHARMACEUTICAL INGREDIENT VIA INHALATION
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A new formulation of dehydrated lipid vesicles employs a vesicle preserver and permits the control of release and delivery of active pharmaceutical ingredients into the respiratory system for treatment in particular of asthma. The typical formulation provides controlled release of the active pharmaceutical ingredient from 0% to 100% from 0 to 72 hours after inhalation, changes the systemic administration to topical administration, allows prolonged therapeutic period for one administration, increased stability, with reduced dose, reduced systemic side effects, reduced toxicity.
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- Metal-free activation of C-C multiple bonds through halide ion pairs: Diels-Alder reactions with subsequent aromatization
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Imidazolium and ammonium halides, both in homogeneous phase or immobilized on mesoporous silica, proved able to promote the aromatization reaction of Diels-Alder adducts under ethylene and H2 elimination. These observations point to the increased nucleophilicity of such halide ions. They also open the possibility to employ such ion pairs as nucleophilic organocatalysts, for example, as substitutes for phosphines or amines.
- Kaper, Helena,Antonietti, Markus,Goettmann, Frédéric
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p. 4546 - 4549
(2008/09/21)
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- Carboxylation and esterification of functionalized arylcopper reagents
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Functionalized arylcopper reagents have been produced in good yields at 25 °C from activated copper and the corresponding functionalized aryl iodides without the need of traditional organolithium or Grignard precursors. These organocopper compounds will undergo carboxylation with CO2 to form the corresponding copper benzoates. In turn, these salts can be acidified to produce the functionalized aryl acids or treated with appropriate alkyl halides in the presence of a dipolar aprotic solvent to generate the corresponding aryl esters. This methodology permits the formation of functionalized organic acids and esters that could not be generated by the carboxylation of organomagnesium compounds.
- Ebert, Greg W.,Juda, Wayne L.,Kosakowski, Robert H.,Ma, Bing,Dong, Liming,Cummings, Keith E.,Phelps, Mwita V. B.,Mostafa, Adel E.,Luo, Jianyuan
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p. 4314 - 4317
(2007/10/03)
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- Method of producing dimethyl phthalate from naphthalene based chemicals
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The present invention results to an improved and environment friendly method of producing dimethyl phthalate of about 99% purity from naphthalene based chemicals, said method comprising steps of mixing phthalic anhydride with methanol in the ratio ranging between 2:3 to 3:2, adding catalyst(s) to the mixture wherein, the ratio of phthalic anhydride and the catalyst is ranging between 3:1 to 15:1, adding a promoter to the resultant of step (b) wherein, the promoter is in the range of 1.5 to 2.0% by weight of phthalic anhydride, refluxing the resulted mixture at a temperature ranging between 60 to 100° C., for time duration ranging between 6 to 12 hrs. in the presence of benzene, wherein the ratio of benzene phthalic anhydride is in the range of 1:5 to 2:1 to obtain distillate, neutralizing the residue with about 10% caustic soda, extracting the neutralized residue with the benzene, distilling at the temperature ranging between 140 to 150° C. under 10 mm of mercury to obtain dimethyl phthalate.
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- METHOD OF PRODUCING DIMETHYL PHTHALATE FROM NAPHTHALENE BASED CHEMICALS
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The present invention results to an improved and environment friendly method of producing dimethyl phthalate of about 99% purity from naphthalene based chemicals, said method comprising steps of mixing phthalic anhydride with methanol in the ratio ranging between 2:3 to 3:2, adding catalyst(s) to the mixture wherein, the ratio of phthalic anhydride and the catalyst is ranging between 3:1 to 15:1, adding a promoter to the resultant of step (b) wherein, the promoter is in the range of 1.5 to 2.0% by weight of phthalic anhydride, refluxing the resulted mixture at a temperature ranging between 60 to 100°C, for time duration ranging between 6 to 12 hrs. in the presence of benzene, wherein the ratio of benzene phthalic anhydride is in the range of 1:5 to 2:1 to obtain distillate, neutralizing the residue with about 10% caustic soda, extracting the neutralized residue with the benzene, distilling at the temperature ranging between 140 to 150°C under 10mm of mercury to obtain dimethyl phthalate.
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- Cation-exchange resin-catalysed acylations and esterifications in fine chemical and perfumery industries
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Acylation and esterification reactions are typically carried out by using homogeneous acids as catalysts which can be profitably replaced with heterogeneous solid acid catalysts to develop green chemistry. Solid acids that give the desired level of activity but which can be easily removed from the reaction mixture with no residual inorganic contamination of the organic products offer obvious advantages over existing methods. This contribution is concerned with eco-friendly synthesis of some commercially valuable products such as p-methoxyacetophenone, dimethyl phthalate, diethyl phthalate, methyl anthranilate, methyl salicylate, and methyl p-hydroxybenzoate (methyl paraben). The specifications require the esters to be free of halide impurities on ppm level for perfumery use, and thus use of chlorine-containing agents or catalysts must be avoided. The following catalysts were evaluated: Amberlyst-36, Bayer K2441, Amberlyst-15, Dowex 50Wx8, Indion-130, Deloxane ASP, Filtrol-24 clay, K-10 Montmorrilonite clay, and sulphated zirconia. Anisole was acylated with acetic anhydride to get 100% selectivity of p-methoxyacetophenone, and Amberlyst-36 was found to be the most active and reusable catalyst. A kinetic model is also presented. Amberlyst-36 was also the most active catalyst for the esterification reactions.
- Yadav,Mujeebur Rahuman
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p. 706 - 713
(2013/09/06)
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- Monitoring of phthalic acid monoesters in river water by solid-phase extraction and GC-MS determination
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An analytical method for monitoring 10 phthalic acid monoesters in river water was investigated by solid-phase extraction, methylation with diazomethane, and GC-MS. Two cartridge-type solid phases packed with octadesyl-coated silica (C18) and styrenedivinyl polymer (PS-2) and one disk-type solid phase made from octadesyl-coated styrene-divinylbenzene polymer (SDB-XD) were investigated in solid-phase extraction. PS-2 gave the highest recoveries of the three solid phases, and recoveries of more than 80% of the monoesters in filtered water samples were obtained at pH 2 to 3 with PS-2 at the spiked level of 0.1 μg L-1, except for monomethyl-phthalate (MMP), in which more than 72% of the monoesters were recovered. For the monoesters in the suspended solids (SS), an acidic methanol extract of SS was added to purified water acidified to pH 2, and the monoesters were extracted with PS-2. The recoveries of the monoesters in SS were more than 80%, but the recoveries of MMP were more than 57%. The method detection limit (MDL) of each phthalic acid monoester in 500 mL of water sample and in 2 mg of dry weight of SS ranged from 0.010 to 0.030 μg L-1 and from 1 to 11 μg g-1 respectively. Monitoring of phthalic acid monoesters in the Tama River in Tokyo was conducted every month from March 1999 to February 2000 using the present method. MMP, mono-n-butyl-phthalate (MBP), and mono-(2-ethylhexyl)-phthalate (MEHP) were detected at concentrations of 0.030-0.0340, 0.010-0.480, and 0.010-1.30 μg L-1. respectively, in the filtered water samples but were not detected in SS. Dimethyl-phthalate (DMP), di-n-butyl-phthalate (DBP), and di-(2-ethylhexyl)-phthalate (DEHP) were detected in the river water at concentrations of 0.010-0.092, 0.008-0.540, and 0.013-3.60 μg L-1, respectively. Diethyl-, di-iso-butyl-, and benzylbutyl-phthalates were also detected at concentrations of nanograms per liter, whereas the corresponding monoesters did not appear. The concentrations of MBP and MEHP in the river water were slightly lower than those of the corresponding diesters at the majority of sampling sites and sampling times.
- Suzuki,Yaguchi,Suzuki,Suga
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p. 3757 - 3763
(2007/10/03)
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- Process for producing carboxylic acid esters and catalysts therefor
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A process for producing carboxylic acid esters by the following steps: a) preparation of a reaction mixture containing an alcohol and a carboxylic acid and/or a carboxylic anhydride and/or a carboxylic acid ester and or a partially esterified carboxylic acid, b) heating of this mixture to the suitable reaction temperature in the presence of a solid polysiloxane insoluble in the reaction medium and having sulphonic acid groups with intensive thorough mixing accompanied by continuous separation of the reaction water which forms, wherein the polysiloxane used as the catalyst in modified by treatment with a soluble aluminum, titanium or zirconium compound, and the spherical particles thereof have a diameter of 0.01 to 3 mm, a specific surface of 0.1 to 1200 m2 /g, a specific pore volume of 0.01 to 6.0 ml/g and a bulk density of 50 to 1000 g/l.
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