- Two Are Better Than One: A Design Principle for Ultralong-Persistent Luminescence of Pure Organics
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Because of their innate ability to store and then release energy, long-persistent luminescence (LPL) materials have garnered strong research interest in a wide range of multidisciplinary fields, such as biomedical sciences, theranostics, and photonic devices. Although many inorganic LPL systems with afterglow durations of up to hours and days have been reported, organic systems have had difficulties reaching similar timescales. In this work, a design principle based on the successes of inorganic systems to produce an organic LPL (OLPL) system through the use of a strong organic electron trap is proposed. The resulting system generates detectable afterglow for up to 7 h, significantly longer than any other reported OLPL system. The design strategy demonstrates an easy methodology to develop organic long-persistent phosphors, opening the door to new OLPL materials.
- Alam, Parvej,Leung, Nelson L. C.,Liu, Junkai,Cheung, Tsz Shing,Zhang, Xuepeng,He, Zikai,Kwok, Ryan T. K.,Lam, Jacky W. Y.,Sung, Herman H. Y.,Williams, Ian D.,Chan, Christopher C. S.,Wong, Kam Sing,Peng, Qian,Tang, Ben Zhong
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- Tergal Gland Secretion of the Rove Beetle Aleochara pseudochrysorrhoa (Staphylinidae: Aleocharinae): Chemical Composition and Biological Roles
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Aleochara pseudochrysorrhoa has a glandular complex known as the tergal gland. Generally, the tergal gland secretion (TGS) has been described to have defensive function, but some reports point to a possible secondary function of this complex. For example, the TGS of the related species A. curtula has been demonstrated to possess an important role in intraspecies communication. In this work, we describe the chemical composition of the TGS of A. pseudochrysorrhoa males and females. Eleven compounds were identified based on GC/MS and GC-FT-IR analyses, retention indexes and derivatization products. Furthermore, a brief study regarding the biological function of the TGS in mating behavior is provided, in which the stimulation of male grasping response reaction by female TGS proved to be dependent on concentration.
- da Silva, Maycon R.,Vidal, Diogo M.,Figueiredo, Leonardo,Bandeira, Pamela T.,Bergmann, Jan,Zarbin, Paulo H. G.
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- Lipophilic ion aromaticity is not important for permeability across lipid membranes
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To clarify the contribution of charge delocalization in a lipophilic ion to the efficacy of its permeation through a lipid membrane, we compared the behavior of alkyl derivatives of triphenylphosphonium, tricyclohexylphosphonium and trihexylphosphonium bo
- Aleksandrova, Ekaterina V.,Antonenko, Yuri N.,Kirsanov, Roman S.,Korshunova, Galina A.,Kotova, Elena A.,Luzhkov, Victor B.,Rokitskaya, Tatyana I.,Tashlitsky, Vadim N.
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Read Online
- Rh2(II)-Catalyzed intermolecular N-Aryl aziridination of olefins using nonactivated N atom precursors
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The development of the first intermolecular Rh2(II)-catalyzed aziridination of olefins using anilines as nonactivated N atom precursors and an iodine(III) reagent as the stoichiometric oxidant is reported. This reaction requires the transfer of an N-aryl nitrene fragment from the iminoiodinane intermediate to a Rh2(II) carboxylate catalyst; in the absence of a catalyst only diaryldiazene formation was observed. This N-aryl aziridination is general and can be successfully realized by using as little as 1 equiv of the olefin. Di-, tri-, and tetrasubstituted cyclic or acylic olefins can be employed as substrates, and a range of aniline and heteroarylamine N atom precursors are tolerated. The Rh2(II)-catalyzed N atom transfer to the olefin is stereospecific as well as chemo- and diastereoselective to produce the N-aryl aziridine as the only amination product. Because the chemistry of nonactivated N-aryl aziridines is underexplored, the reactivity of N-aryl aziridines was explored toward a range of nucleophiles to stereoselectively access privileged 1,2-stereodiads unavailable from epoxides, and removal of the N-2,4-dinitrophenyl group was demonstrated to show that functionalized primary amines can be constructed.
- Deng, Tianning,Mazumdar, Wrickban,Yoshinaga, Yuki,Patel, Pooja B.,Malo, Dana,Malo, Tala,Wink, Donald J.,Driver, Tom G.
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supporting information
p. 19149 - 19159
(2021/11/23)
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- Phosphonium-based ionic liquids: Economic and efficient catalysts for the solvent-free cycloaddition of CO2 to epoxidized soybean vegetable oil to obtain potential bio-based polymers precursors
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A series of phosphonium-based ionic liquids have been prepared in one step in a simple way from inexpensive feedstocks. The prepared ionic liquids have been successfully tested as catalysts in the solvent-free cycloaddition reaction of CO2 to an epoxidized soybean oil to obtain carbonated soybean oil that can be potentially employed as bio-monomer in the synthesis for bio-based polymers. The catalytic performance of these ionic liquids was compared to the widely used and benchmark catalyst in CO2 cycloaddition to epoxides reaction, namely tetrabutylammonium bromide at different reaction conditions. The influence of some reaction parameters such as temperature, CO2 pressure, reaction time and catalyst amount was studied. It has been found that the solubility of the prepared ionic liquids in the reaction media (epoxidized soybean oil) is a key factor that limits the catalytic performance of some of the synthesized ionic liquids. All prepared ionic liquids have shown higher thermal stability that the benchmark catalyst and three of them have shown superior catalytic performance. The best results in terms of conversion and selectivity have been obtained with dodecyltriphenylphosphonium bromide (5) achieving almost full conversion (99.8%) and excellent selectivity (84.0%) after 5 h reaction at 160 oC and 40 bar of CO2. Outstanding results compared to those reported in the literature with similar catalysts in the solvent-free CO2 cycloaddtion to an epoxidized soybean oil to obtain the corresponding carbonated oil have been achieved. Considering the facile synthesis of catalyst 5, the large availability and non-expensive of the feedstocks and its catalytic performance it can be considered a valuable and green alternative for CO2 fixation to epoxidized vegetable oil.
- Centeno-Pedrazo, A.,Freixa, Z.,Garcia-Suarez, E. J.,Perez-Arce, J.,Prieto-Fernandez, S.
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- Mechanism-Inspired Design of Bifunctional Catalysts for the Alternating Ring-Opening Copolymerization of Epoxides and Cyclic Anhydrides
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Advances in catalysis have enabled the ring-opening copolymerization of epoxides and cyclic anhydrides to afford structurally and functionally diverse polyesters with controlled molecular weights and dispersities. However, the most common systems employ b
- Abel, Brooks A.,Lidston, Claire A. L.,Coates, Geoffrey W.
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supporting information
p. 12760 - 12769
(2019/08/26)
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- Ionic liquid functionalized acid orange for organic solvent and preparation method thereof
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The invention relates to ionic liquid functionalized acid orange for an organic solvent and a preparation method thereof. The preparation method for the ionic liquid functionalized acid orange for theorganic solvent provided by the invention comprises the following steps: first, first, reacting triphenylphosphine and slightly excessive bromoalkane, and washing and purifying by using ethyl acetateto prepare alkyl triphenyl bromide; performing neutral reaction on acidified acid orange and silver carbonate, and washing and drying to prepare acid orange silver salt; then, respectively performingion exchange on the prepared acid orange silver salt and different alkyl triphenyl bromide to prepare a series of novel ionic liquid functionalized acid orange which can be dissolved in a plurality of organic solvents. The synthesis reaction conditions are mild and the post-treatment is simple. The type of ionic liquid functionalized acid orange has good solubility in the plurality of the organicsolvents, and is an azo dye and an acid base indicator which can be used for the organic solvent.
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Paragraph 0041-0044
(2019/08/20)
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- Exploring London Dispersion and Solvent Interactions at Alkyl–Alkyl Interfaces Using Azobenzene Switches
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Interactions on the molecular level control structure as well as function. Especially interfaces between innocent alkyl groups are hardly studied although they are of great importance in larger systems. Herein, London dispersion in conjunction with solvent interactions between linear alkyl chains was examined with an azobenzene-based experimental setup. Alkyl chains in all meta positions of the azobenzene core were systematically elongated, and the change in rate for the thermally induced Z→E isomerization in n-decane was determined. The stability of the Z-isomer increased with longer chains and reached a maximum for n-butyl groups. Further elongation led to faster isomerization. The origin of the intramolecular interactions was elaborated by various techniques, including 1H NOESY NMR spectroscopy. The results indicate that there are additional long-range interactions between n-alkyl chains with the opposite phenyl core in the Z-state. These interactions are most likely dominated by attractive London dispersion. This work provides rare insight into the stabilizing contributions of highly flexible groups in an intra- as well as an intermolecular setting.
- Strauss, Marcel A.,Wegner, Hermann A.
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supporting information
p. 18552 - 18556
(2019/11/19)
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- Iron-Nickel Dual-Catalysis: A New Engine for Olefin Functionalization and the Formation of Quaternary Centers
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Alkene hydroarylation forms carbon-carbon bonds between two foundational building blocks of organic chemistry: olefins and aromatic rings. In the absence of electronic bias or directing groups, only the Friedel-Crafts reaction allows arenes to engage alkenes with Markovnikov selectivity to generate quaternary carbons. However, the intermediacy of carbocations precludes the use of electron-deficient arenes, including Lewis basic heterocycles. Here we report a highly Markovnikov-selective, dual-catalytic olefin hydroarylation that tolerates arenes and heteroarenes of any electronic character. Hydrogen atom transfer controls the formation of branched products and arene halogenation specifies attachment points on the aromatic ring. Mono-, di-, tri-, and tetra-substituted alkenes yield Markovnikov products including quaternary carbons within nonstrained rings.
- Green, Samantha A.,Vásquez-Céspedes, Suhelen,Shenvi, Ryan A.
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supporting information
p. 11317 - 11324
(2018/09/18)
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- The compound, composition, and display device
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PROBLEM TO BE SOLVED: To provide a compound capable of elevating an upper limit temperature where a SmC (smectic-C) phase of a liquid crystal can exist, broadening a temperature width of the SmC phase or enlarging a tilt angle of the SmC phase, and to provide a liquid crystal composition comprising the compound and a display element including the liquid crystal composition.SOLUTION: [1] The compound is expressed by general formula (i) shown below. In general formula (i), R and R' each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 9 carbon atoms; A1, A2 and A3 each independently represent a 1,4-phenylene group or a 2,3-difluoro-1,4-phenylene group; m represents an integer of 1 to 10; and Y represents a cyclohexylene group, a phenylene group, a bicyclooctylene group or a dialkylsilylene group.
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Paragraph 0102-0104
(2017/07/26)
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- A concise and efficient synthesis of tetrahydroquinoline alkaloids using the phase transfer mediated Wittig olefination reaction
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The present study describes the total synthesis of 1,2,3,4-tetrahydroquinoline alkaloids (±)-galipinine, (±)-cuspareine, (±)-galipeine and (±)-angustureine, in three steps and high yields (78%, 76%, 74%, and 66%, respectively) from common aldehyde and the ylide respectives. The key step of this approach is based on an unusual Wittig reaction by using the phase transfer medium (aq. NaOH/CH2Cl2 1:1 or t-BuOK/t-BuOH/CH2Cl2 1:1), affording olefinic intermediates in high yields.
- Diaz-Mu?oz, Gaspar,Isidorio, Raquel Geralda,Miranda, Izabel Luzia,de Souza Dias, Gabriel Nunes,Diaz, Marisa Alves Nogueira
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supporting information
p. 3311 - 3315
(2017/07/27)
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- Kinetics and mechanistic investigation of epoxy-anhydride compositions cured with quaternary phosphonium salts as accelerators
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Mechanism and curing kinetics of bisphenol A epoxy resin-iso-methyltetrahydrophthalic anhydride compositions using quaternary phosphonium salts as accelerators were investigated by differential scanning calorimetry (DSC) and electrospray mass-spectrometry (ESI-MS). The DSC method was applied to investigate curing kinetics and apparent activation energy values for the overall curing process. The DSC results showed that some of the phosphonium salts lead to a lower activation energy, that means they are more effective accelerators for the curing of epoxy-anhydride systems. The mechanism of curing was studied by ESI-MS using the model reaction of epichlorohydrin (E) with phthalic anhydride (PA) in the presence of phosphonium salts or 2-methylimidazole. Products containing the alkyl moiety of the phosphonium salt in form of alkyl esters could be identified. This suggests that the phosphonium salts activate the anhydride by electrophilic attack.
- Amirova, Lyaysan R.,Burilov, Alexander R.,Amirova, Liliya M.,Bauer, Ingmar,Habicher, Wolf D.
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p. 1088 - 1097
(2016/03/12)
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- Organoselenium-catalyzed synthesis of oxygen- and nitrogen-containing heterocycles
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A new and efficient approach for the synthesis of oxygen and nitrogen heterocycles by organoselenium catalysis has been developed. The exo-cyclization proceeded smoothly under mild conditions with good functional group tolerance and excellent regioselectivity. Mechanistic studies revealed that 1-fluoropyridinium triflate is key for oxidative cyclization.
- Guo, Ruizhi,Huang, Jiachen,Huang, Haiyan,Zhao, Xiaodan
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supporting information
p. 504 - 507
(2016/02/18)
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- Design, synthesis and SAR study of novel sulfonylureas containing an alkenyl moiety
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A series of sulfonylurea compounds was designed and synthesized via introducing an alkenyl moiety into the aryl-5 position and most title compounds exhibited enhanced antifungal activities and limited herbicidal activities compared with chlorsulfuron. Then, a CoMSIA calculation for antifungal activities was carried out to establish a 3D-QSAR model in which a cross-validated q2 of 0.585 and a correlation coefficient r2 of 0.989 were obtained. The derived model revealed that hydrophobic and electrostatic fields were the two most important factors for antifungal activity. Structure optimization was performed according to the CoMSIA model and compound 9z was found to be as potent as chlorothalonil in vitro against C. cornigerum, the pathogen of the wheat sharp eyespot disease. In order to study the fungicidal mechanism, 9z was successfully docked into yeast AHAS using a flexible molecular docking method and the resulting binding pattern was similar to that of chlorimuron-ethyl, indicating that the antifungal activity of compounds 9 was probably due to the inhibition of fungal AHAS.
- Wei, Wei,Cheng, Dandan,Liu, Jingbo,Li, Yuxin,Ma, Yi,Li, Yonghong,Yu, Shujing,Zhang, Xiao,Li, Zhengming
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p. 8356 - 8366
(2016/09/09)
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- METHOD FOR PRODUCING AVENACIOLIDES AND USES THEREOF
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Disclosed herein are novel uses of avenaciolide derivatives and the preparation method of producing the same. The avenaciolide derivatives may suppress or inhibit the growth of gram-positive bacteria, including the notorious methicillin-resistant Staphylococcus aureus. Accordingly, the avenaciolides derivatives are potential lead compounds for the development of next generation antibiotics for the treatment of disease and/or disorders related to infection caused by gram-positive bacteria.
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Paragraph 0159; 0160
(2016/10/31)
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- Catalytic, oxidant-free, direct olefination of alcohols using Wittig reagents
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Reported here is the catalytic, acceptorless coupling of alcohols with in situ generated, non-stabilized phosphonium ylides to form olefins as major products. The reaction uses low catalyst loadings and does not require added oxidants. Hydrogenation of the product is minimized and the reaction leads to Z (aliphatic) or E (benzylic) stereospecificity.
- Khaskin,Milstein
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supporting information
p. 9002 - 9005
(2015/05/27)
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- Synthesis of the peptaibol framework of the anticancer agent culicinin D: Stereochemical assignment of the AHMOD moiety
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The postulated structure of the potent anticancer peptaibol culicinin D has been synthesized using Fmoc-based solid-phase peptide synthesis (SPPS). Comparison of the 1H NMR data for the reported structure of culicinin D with the data obtained for the two synthetic polypeptides epimeric at C-6 in the AHMOD unit established the C-6 stereochemistry of the AHMOD residue in the natural product to be (R).
- Hung, Kuo-Yuan,Harris, Paul W. R.,Brimble, Margaret A.
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supporting information
p. 5784 - 5787
(2013/01/15)
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- Convenient synthesis of D- and L-xylo-1,2,3,4-alkane tetrols from a D-gluco-configured common building block
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D-gluco-Configured building block derived from d-(+)-gluconolactone has served as a common chiral template for the synthesis of enantiopure d- and l-xylo-configured 1,2,3,4-alkane tetrols. This has enabled synthesis of medicinally important guggultetrols and their enantiomers from a common starting point. Wittig and Grignard reactions are the key steps used for the incorporation of lipophilic chain.
- Borkar, Santosh Ramdas,Manjunath, Beedimane Narayana,Balasubramaniam, Sivaraman,Aidhen, Indrapal Singh
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- Highly selective iridium-catalyzed asymmetric hydrogenation of trifluoromethyl olefins: A new route to trifluoromethyl-bearing stereocenters
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Fluorine-containing compounds are useful in many applications ranging from pharmaceuticals to ferroelectric crystals. We have developed a new, highly enantioselective synthetic route to trifluoromethyl-bearing stereocenters in up to 96% ee via asymmetric hydrogenation using N,P-ligated iridium catalysts. We also hydrogenated an isomeric mixture of olefins; this reaction gave the hydrogenation product highly enantioselectively (87% ee), and only the E isomer was present after the reaction had reached 56% conversion.
- Engman, Mattias,Cheruku, Pradeep,Tolstoy, Paeivi,Bergquist, Jonas,Voelker, Sebastian F.,Andersson, Pher G.
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supporting information; experimental part
p. 375 - 378
(2009/11/30)
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- Reaction of thiolesters with nitrogen ylides
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The pairing of unstabilized nitrogen ylides generated in situ with functionalized thiolesters under ambient conditions resulted in a new intramolecular carbon-carbon bond forming reaction. The scope of the reaction was illustrated with a series of substit
- Voltrova, Svatava,Srogl, Jiri
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supporting information; experimental part
p. 1677 - 1679
(2009/04/06)
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- Fluorinated butanolides and butenolides - Part 9. Synthesis of 2-(trifluoromethyl)butan-4-olides by Wittig reaction using methyl 3,3,3-trifluoropyruvate
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2-(Trifluoromethyl)butan-4-olides 13 and 14 were prepared by a three-step synthesis starting from a Wittig reagent and methyl 3,3,3-trifluoropyruvate (1) as a building block. The Wittig reaction of (2-oxoalkyl)triphenylphosphonium bromides with pyruvate 1 gave intermediate 4-oxobutenoates 8 and 9, which were stepwise selectively reduced with zinc borohydride firstly at the double bond and subsequently at the oxo group to afford unstable 4-hydroxy-2-trifluoromethylalkanoates 11 and 12, which cyclised spontaneously to the end butenolides 13 and 14.
- Palecek, Jiri,Kvicala, Jaroslav,Paleta, Oldrich
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p. 177 - 183
(2007/10/03)
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- Insect pheromones and their analogs. LXI. Synthesis of 4E,10Z-tetradecadien-1-ylacetate, a component of the Lithocolettis ringoniella sex pheromone
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A new scheme for synthesizing 4E,10Z-tetradecadien-1-ylacetate, the principal component of the apple leaf miner (Lithocolettis ringoniella) sex pheromone, is developed using a highly stereoselective Claisen rearrangement.
- Shakhmaev,Vakhidov,Zorin,Odinokov
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p. 282 - 284
(2007/10/03)
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- Synthesis and biological activity of new diarylalkenes
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Condensation of 5-nitro-, 3-chloro-, and 5-chlorosalicylic acid with formaldehyde afforded dimeric disalicylmethanes which were O-methylated with dimethyl sulfate and oxidized with chromium(VI) oxide to give the diarylketones 10, 11, 12. Wittig reaction with ylides obtained by deprotonation of alkyltriphenylphosphonium salts with sodium bis (trimethylsilyl)amide yielded a series of diarylalkenes. Some of the obtained compounds showed high antimicrobial activity in vitro against Bacillus subtilis and Mycobacterium smegmatis.
- Golebiewski, W. Marek,Cieniecka-Ros?onkiewicz,Szybinska
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- Bis(2,6-dimethoxyphenyl) sulfide, selenide and telluride, and their derivatives
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2,6-Dimethoxyphenyl derivatives of sulfur, selenium, and tellurium, such as ΦEEΦ, Φ2E, ΦSeH, [MeΦ2E]X (X = MeSO4, ClO4), Φ2EO · xH2O, [Φ2EOH]ClO4, [Φ2EOR]Cl
- Wada, Masanori,Nobuki, Shin-Ichi,Tenkyuu, Yoshinori,Natsume, Satoko,Asahara, Masahiro,Erabi, Tatsuo
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p. 282 - 289
(2007/10/03)
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- Synthesis of α-tocopherol analogues
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A range of α-tocopherol analogues of varying side-chain length and structure has been prepared by the Wittig reaction of alkyltriphenylphosphonium bromides with either 6-benzyloxy-2,5,7,8-tetramethylchroman-2-carbaldehyde (8) or 6-acetoxy-2,5,7,8,-tetramethylchroman-2-carbaldehyde (14). These analogues include 2-hexyl-2,5,7,8-tetramethylchroman-6-ol (11), 2-heptyl-2,5,7,8-tetramethylchroman-6-ol (12) and 2,5,7,8-tetramethyl-2-(pent-l-enyl)chroman-6-ol (15). Methoxycarbonylmethyl 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (2) was formed by reaction of the triethylammonium salt of trolox (1) with methyl bromoacetate. Reaction of methoxycarbonylmethyltriphenylphosphonium bromide (16) with (8) did not produce the expected methyl 3-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)prop-2-enoate (17), but rather 4-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)but-3-en-2-one (22). A proposed mechanism for this unusual reaction is discussed.
- Suarna, Cacang,Dean, Roger T.,Southwell-Keely, Peter T.
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p. 1129 - 1135
(2007/10/03)
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- Reactions of tris(2,6-dimethoxyphenyl) arsine, tris(2,6-dimethoxyphenyl) stibine and tris(2,6-dimethoxyphenyl) bismuthine and their derivatives
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Tris(2,6-dimethoxyphenyl)arsine and tris(2,6-dimethoxyphenyl)stibine (Φ3M(Φ = 2,6-(MeO)2C6H3; M = As an Sb)) reacted with common alkyl halides (RX) to give [Φ3M-R]X, while Φ3Bi was unreactive in benzene, or it decomposed in hot alcohols. The reactions of Φ3M (As,Sb) with butyl bromide in acetonitrile were much faster than that of triphenylphosphine. Treatments of Φ3M (P,As,Sb) with N-bromosuccinimide (NBS) gave [Φ3M-OH]Br, while Φ3Bi decomposed to give 1-bromo-2,6-dimethoxybenzene. [Φ3M-OH]Br are soluble in water, and the acidity decreased in the order M = P > As > Sb. Treatments of Φ3M (As,Sb) with aqueous hydrogen peroxide gave the oxides as hydrates, Φ3MO. xH2O (x = 1 for M = As and x = 3 for M = Sb), while Φ3Bi was unreactive or decomposed. Φ3PO was brominated by NBS to give Φ′3PO.H2O (Φ′ = 3-Br-2,6-(MeO)2C6H2), which did not react with perchloric acid. In contrast, Φ3MO.xH2O (P,As,Sb) reacted with the acid to form the stable hydroxyonium salts [Φ3M-OH]ClO4. [Φ3P-OH]ClO4 formed crystals of stable 1 : 1 adducts with a variety of amines. [Φ3As-OH]ClO4 formed 1 : 1 adducts when treated with excess amounts of several amines (triethylamine,diethylamine,isobutylamine and piperidine), but they were unstable to leave amines by recrystallization. [Φ3Sb-OH]ClO4 formed unstable adducts with these amines, or it did not form. [Φ3P-SH]ClO4 formed 1 : 1 adducts with several amines, or it was deprotonated to give Φ3PS. Φ3MO.xH2O (P,As) reacted with common RX (X = Br or I) to give [Φ3M-OR]X, but Φ3SbO.3H2O reacted to give [Φ3Sb-OH]X. [Φ3P-OR]X decomposed reversibly to give Φ3PO in solutions, although [Φ3M-OR]ClO4 (P,As) could be recrystallized.
- Wada, Masanori,Miyake, Shin-Ichi,Hayashi, Shinji,Ohba, Hiroshi,Nobuki, Shin-Ichi,Hayase, Shuichi,Erabi, Tatsuo
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- Crystal Structure and Chemical Properties of Tris(2,6-dimethoxyphenyl)phosphine Selenide
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The X-ray crystal structure of the title compound, Φ3PSe [Φ = 2.6-(MeO)2C6H3], showed that the P=Se bond distance [2.136(2) A] was the longest among those of the reported triarylphosphine selenides, that the P-C
- Wada, Masanori,Hayase, Shuichi,Fujiwara, Masanobu,Kawaguchi, Tetsuji,Iwasaki, Toshio,Uo, Akira,Erabi, Tatsuo
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p. 655 - 664
(2007/10/03)
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- Kinetics of the reaction between triphenylphosphine and some haloalkanes
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Kinetics of reactions RX + (C6H5)2P -> (C6H5)3PR+X- (R = CCl3, CBr3, CH2Br, C4H9 and X = Br, Cl, I) have been studied at different temperatures and in different dielectric media.The values of second order rate constants of the reactions with tetrahalomethanes are much higher than those with partially halogenated alkanes.This suggests that the reaction may be of charge transfer type with tetrahalomethanes while with other haloalkanes it is simple nucleophilic substitution reaction of SN2 type.
- Jain, D V S.,Chadha, R
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p. 929 - 935
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF ALKYLPHOSPHONIUM SALTS
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The reaction of methanol and its homologs with Ph3P in 48percent aqueous hydrobromic acid provides alkyltriphenylphosphonium salts in quantitative yields.
- Hercouet, A.,Corre, M. le
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p. 279 - 280
(2007/10/02)
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- REACTIONS EN MILIEU HETEROGENE SOLIDE-LIQUIDE FAIBLEMENT HYDRATE : LA REACTION DE WITTIG DANS LE SYSTEME HYDROXIDES ALCALINS/SOLVANT ORGANIQUE APROTIQUE
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The Wittig reaction carried out in a slightly hydrated solid-liquid media constituted by a solid alkaline hydroxide and an organic phase which includes the phosphonium salt and the aldehyde leads easily to the corresponding alkene with very good yields specially with furanic aldehydes.The ylide formation at the interface appears as the most important step of this condensation.
- Le Bigot, Yves,Delmas, Michel,Gaset, Antoine
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p. 1057 - 1072
(2007/10/02)
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- COMMUNICATION. Utilisation du Bromhydrate de Triphenylphosphine pour la Synthese de Sels d'Alkyltriphenylphosphonium
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Alkyltriphenylphosphonium salts can be obtained with good yields from the condensation between alkyl chlorides and triphenylphosphonium bromide.
- Hercouet, A.,Corre, M. Le
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p. 111 - 114
(2007/10/02)
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- SYNTHESIS OF PHEROMONES, III IMPROVED AND STEREOCONTROLLED SYNTHESES OF ISOMERIC MIXTURES OF 8-DODECEN-1-YL ACETATES
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Simple syntheses have been developed for the preparation of isomeric mixtures of 8-dodecen-1-yl acetates, which are active sex pheromones of many insect species.The Wittig reaction under modified conditions and reduction of the C-C triple bond were applied for the stereocontrolled formation of the C-C double bond.
- Vinczer, Peter,Juvanecz, Zoltan,Novak, Lajos,Szantay, Csaba
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p. 737 - 748
(2007/10/02)
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- REACTIONS EN MILIEU HETEROGENE SOLIDE-LIQUIDE FAIBLEMENT HYDRATE III - LA REACTION DE WITTIG DANS LE SYSTEME CARBONATES ALCALINS/SOLVANT ORGANIQUE PROTIQUE
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The use of alkaline carbonates in a slighty hydrated solid-liquid protic organic media allowed the synthesis of alkenes from polyfunctional aldehydes with high yield in a E preferential stereochemistry specially with non-stabilized ylides.It has been shown that the decomposition of the threo betain acts as the determining step of the reaction.
- Le Bigot, Y.,El Gharbi, R.,Delmas, M.,Gaset, A.
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p. 3813 - 3824
(2007/10/02)
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- 1H-NMR- AND MOESSBAUER INVESTIGATIONS ON THE ION PAIRS OF TETRACHLOROFERRATE(III) ANION WITH QUATERNARY PHOSPHONIUM CATIONS
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Paramagnetic ion pairs were investigated by 1H-NMR and Moessbauer spectroscopy in chloroform and dimethyl sulphoxide.It has been shown that the chemical shifts of 1H-NMR peaks arise from a combination of contact and pseudocontact interactions of opposite sign, and the ratio of interactions was definitely influenced by the extent of solvation.On the basis of Moessbauer measurements it was shown that the change of the cation size had an effect on the electron delocalization and symmetry conditions of iron(III) in solid samples, too.In concentrated frozen solutions of ion pairs, different interactions were indicated by Moessbauer spectros copy in chloroform and dimethyl sulphoxide, in accordance with 1H-NMR results.However, in dilute solution such an anion-solvent interaction was observed directly, which could be shown by the NMR method only indirectly.
- Vincze, L.,Papp, S.
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p. 153 - 162
(2007/10/02)
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- Apparent Molal Volumes of Phosphonium Halides at 15, 25 and 35 deg C
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The densities of aqueous solutions of the phosphonium halides, Bu4-nPhnPX (n = 0-4), some of which were synthesized from the phosphines, were measured at 15, 25 and 35 deg C.Partial molal volumes at infinite dilution, V0 a
- Takaizumi, Katsuko,Wakabayashi, Toshiki
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p. 809 - 818
(2007/10/02)
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