- Merging structural frameworks of imidazolium, pyridinium, and cholinium ionic liquids with cinnamic acid to tune solution state behavior and properties
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Solubility in water, interactions with the solvent medium and tuning of molecular conformation in the liquid phase are the key issues to discover new biologically active molecules and to understand the mechanisms of their action. In the present article, we report synthesis, structural and biological activity studies, and computational modeling of new ionic compounds. Structural frameworks of well-known imidazolium, pyridinium and cholinium ionic liquids (ILs) were combined with naturally occurring cinnamic acid (CA), which is known to possess a wide spectrum of biological activity. Different combinations of these two structural elements (IL and Cin (cinnamic moiety)) allowed modulating the solubility, physicochemical properties and biological activity of the resulting molecules. A significant increase in the biological activity was achieved for the three studied hybrid molecules - [C4mim-Cin][Cl], [C4py–Cin][Cl], and [C4mim-Cin][Cin]. Multiparameter cytotoxicity mapping was performed to visualize the biological activity of the 28 studied molecules. Detailed experimental investigation and molecular dynamics simulation were performed to gain insight into the structure–activity relationship. Of note, a folding conformational change in the structure of [Cnmim-Cin][Cl] hybrid molecules in solution resulted in a substantial change in chemical reactivity, with the activation energy of the hydrolysis reaction decreasing from 32.1 to 23.9 kcal/mol.
- Ananikov, Valentine P.,Egorova, Ksenia S.,Gordeev, Evgeniy G.,Posvyatenko, Alexandra V.,Seitkalieva, Marina M.,Strukova, Elena N.,Vavina, Anna V.
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- Synthesis of chloroesters by the reaction of ethers with acyl chlorides catalyzed by ZnO
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An efficient method for the synthesis of chloroesters by the reaction of ethers with acyl chlorides catalyzed by nano-ZnO under solvent-free condition at room temperature was described. The method is compatible with a range of ethers including tricyclic ethers, tetracyclic ethers, pentacyclic ethers and hexacyclic ethers and have afforded the products with moderate to good yields. The ZnO could be reused up to three times and the product yield after three cycles is 87%.
- Tang, Yuqi,Feng, Chengliang,Yang, Wanfeng,Ji, Min,Wang, Wei,Chen, Junqing
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- Practical and Selective sp3 C?H Bond Chlorination via Aminium Radicals
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The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine-tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site-selective chlorination of sp3 C?H bonds. This process exploits the ability of protonated N-chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical-chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H-atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp3 C?H chlorination.
- McMillan, Alastair J.,Sieńkowska, Martyna,Di Lorenzo, Piero,Gransbury, Gemma K.,Chilton, Nicholas F.,Salamone, Michela,Ruffoni, Alessandro,Bietti, Massimo,Leonori, Daniele
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supporting information
p. 7132 - 7139
(2021/03/03)
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- Synthesis, in silico study and antimicrobial activity of new piperine derivatives containing substituted δ-esters
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A series of fifteen new piperine-derived diesters was synthesized through the substitution reaction between the salt of piperic acid, obtained through piperine basic hydrolysis, with the δ-chloro-esters, obtained through the cleavage of tetrahydrofuran (THF) with acyl chlorides in the presence of ZnCl2. The final compounds were obtained with yields ranging from 50 to 84% and were characterized by infrared (IR) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR). The new compounds were evaluated in silico in regard to their ADME (absorption, distribution, metabolism, and excretion) properties, and in vitro for their antimicrobial activity against bacteria strains (Staphylococcus aureus and Pseudomonas aeruginosas), yeast fungi (Candida albicans and C. tropicalis) and filamentous fungi (Aspergillus fumigatus, A. flavus and A. niger). The results from the in silico studies of Lipinski's rule of five showed that most compounds present good pharmacological possibilities, and the results from in vitro antimicrobial activity showed that 8 of the 15 synthesized compounds displayed antimicrobial activity, inhibiting the growth of 40-80% of tested strains, with a minimum inhibitory concentration (MIC) interval ranging from 1024 to 256 μg mL-1
- Barbosa-Filho, José M.,Brandao, Maria C. R.,De Athayde-Filho, Petr?nio F.,Dutra, Thalisson F.,Lima, Edeltrudes O.,Lira, Bruno F.,Neto, Hermes Diniz,Trindade, Emmely O.
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p. 2590 - 2602
(2020/11/18)
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- Preparation method and application of alkyl ether sulfonyl fluoride compound
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The invention belongs to the technical field of chemical synthesis methods, and particularly relates to a preparation method of an alkyl ether sulfonyl fluoride compound. The preparation method comprises the following steps: reacting an alkyl ether sodium sulfonate compound with a chlorination reagent to obtain an alkyl ether sulfonyl chloride compound; and reacting the alkyl ether sulfonyl chloride compound with a nucleophilic fluorination reagent to obtain the alkyl ether sulfonyl fluoride compound. A preparation method for the alkyl ether sodium sulfonate compound comprises the following steps: (1) reacting tetrahydrofuran with acetyl chloride to obtain 4-chlorobutyl acetate; (2) carrying out a sulfonation reaction on the 4-chlorobutyl acetate obtained in the step (1) and sodium sulfiteto obtain sodium 4-hydroxybutanesulfonate; and (3) reacting the sodium 4-hydroxybutanesulfonate obtained in the step (2) with sodium hydroxide and brominated alkane to obtain the alkyl ether sodium sulfonate compound. The alkyl ether sulfonyl fluoride compound obtained by using the preparation method can be used as a precursor of an existing perfluorochemical, and has the characteristics that thealkyl ether sulfonyl fluoride compound is easy to degrade, degraded substances have lower toxicity or bioaccumulation and the like.
- -
-
Paragraph 0102-0106
(2020/08/22)
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- Synthesis method of 1,4-butane sultone
-
The invention relates to a synthesis method of 1,4-butane sultone and belongs to the technical field of compound synthesis. The synthesis method takes tetrahydrofuran and acetylchloride as raw materials and comprises the following steps: A, preparation of butylchloroacetate: placing tetrahydrofuran and zinc powder in a container, cooling to 15 DEG C or lower, beginning to dropwise add acetylchloride, after dropwise adding, heating to 45 DEG C, holding the temperature for 8-10 hours, then heating to 60 DEG C, holding the temperature for 1-2 hour, performing pressure reduction to extract butylchloroacetate, and B, preparation of 1,4-butane sultone: allowing butylchloroacetate, sodium sulfite and water to give a heating reflux reaction for 14-16 hour, performing pressure reduction till a solid is separated out, cooling to 45 DEG C or lower, dropwise adding methanol hydrochloride solution, performing stirring for 1-2 hours, cooling to 4-6 DEG C, performing suction filtration, performing pressure reduction on filtrate to extract methanol, water and acetic acid, then heating to 130 DEG C, performing high vacuum pressure reduction cyclization for 0.5-1 hour, heating to 150 DEG C, and thenperforming high vacuum pressure reduction to extract 1,4-butane sultone. The synthesis method is simple; a reaction process is mild and stable; a prepared target product is high in yield and purity,and very low in water content and acid content.
- -
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Paragraph 0010; 0030-0032; 0036-0038; 0042-0044
(2019/06/12)
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- Preparation method of 4-halobutyl acetate
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The invention discloses a preparation method of 4-halobutyl acetate, relates to the preparation method of acetate and aims to solve the technical problems that in an existing method for preparing the4-halobutyl acetate, the reaction time is long, the reaction temperature is high, the cost is high, a toxic reagent is used, the operation is complicated, and the yield is low. The preparation methodcomprises the following steps: mixing and stirring urea, tetrahydrofuran and acetyl halide, naturally cooling to room temperature, adding distilled water, regulating pH (Potential of Hydrogen) to be neutral, carrying out suction filtration, extracting, drying, filtering, and distilling. The 4-halobutyl acetate prepared by the invention structurally contains an ester group and chain end halogen andis a multi-purpose polyfunctional compound. The 4-halobutyl acetate prepared by the invention is prepared from corresponding acyl halide and cyclic ether under catalysis of the urea, and the preparation method is bran-new. A solid byproduct of the preparation method is acyl urea. The preparation method disclosed by the invention has the advantages of simple operation, low cost, safety and high efficiency, environment friendliness and the like.
- -
-
Paragraph 0054-0062; 0068-0069; 0072
(2018/09/20)
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- Palladium(II) acetate catalyzed acylative cleavage of cyclic and acyclic ethers under neat conditions
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During the development of a palladium catalyzed C–H activation cross-coupling reaction involving acyl halides, it was noted that palladium(II) acetate catalyzes the acylative cleavage of tetrahydrofuran (used as a solvent) at room temperature to afford the corresponding 4-chlorobutyl ester derivative. After optimization, the reaction was shown to work well with epoxides, oxetane and tetrahydrofuran, but only barely with oxanes at room temperature. Acyclic ethers systematically failed to react under similar conditions, but underwent complete conversion in a microwave reactor at 100 °C.
- Fotie, Jean,Adolph, Brandy R.,Bhatt, Shreya V.,Grimm, Casey C.
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supporting information
p. 4648 - 4651
(2017/11/15)
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- COMPOUND APPLICABLE TO PHOTOALIGNMENT METHOD AND ITS PHOTOSENSITIVE POLYMER
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PURPOSE: A photosensitive polymer prepared by polymerizing a compound which is proper for photoalignment is provided to prevent static electricity and to manufacture liquid crystal alignment film with high optical uniformity. CONSTITUTION: A compound which is proper to photoalignment is denoted by chemical formula 1. A photosensitive polymer is used by polymerizing the compound of chemical formula 1. A liquid crystal alignment film is manufactured using the photoalignment agent. A liquid crystal display device is manufactured using the photoalignment agent.
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Paragraph 0256-0260
(2017/09/29)
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- Heavier chalcogenone complexes of bismuth(iii)trihalides: Potential catalysts for acylative cleavage of cyclic ethers
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Heavier chalcogenones (S, Se and Te) of imidazole act as versatile ligands to yield a series of mononuclear and dinuclear bismuth(iii)complexes of heavier chalcogenones in excellent yield. These new bismuth heavier chalcogen derivatives are the first structurally characterized molecules, where the bismuth and heavier chalcogen ratio is 1:1. There is only one previous report of a crystal structure of a bismuth(iii)-imidazol selone compound and none with bismuth(iii)-imidazol tellone. The bismuth center in monomeric bismuth chalcogen trihalides depicts pseudo trigonal bipyramidal geometry, while the dimeric bismuth chalcogen trihalides demonstrate distorted square pyramidal geometry. The solid state structures of bismuth chalcogenone derivatives feature rare Bi...π(aryl) interactions. Thus, the centroid of the C6-ring suggests a half sandwich type of bismuth environment in mononuclear and dinuclear bismuth(iii) chalcogenone complexes. Notably, the Bi...π(aryl) interaction is not often noticed for mononuclear bismuth chalcogen compounds. Some of the bismuth(iii) chalcogenone complexes also exhibit C-H...π(aryl), C-H...S and C-H...Cl types of hydrogen bonding. The bismuth-chalcogen bond distance in mononuclear bismuth(iii)tribromide chalcogenone complexes is slightly longer than in mononuclear bismuth(iii)trichloride chalcogenone complexes. A gradual increase in carbon-chalcogen bond distance was observed from the free imidazole-chalcogenone to mononuclear bismuth(iii)trichloride chalcogenones, dinuclear bismuth(iii)trichloride chalcogenones and mononuclear bismuth(iii)tribromide chalcogenones and dinuclear bismuth(iii)tribromide chalcogenones. The UV-vis absorption properties and thermal decomposition properties of imidazol chalcogenones and their bismuth derivatives were investigated. Furthermore, the O-acylative cleavage of cyclic ethers was demonstrated using mononuclear and dinuclear bismuth(iii)complexes of heavier chalcogenones as catalysts. In contrast to bismuth(iii)trichloride and bismuth(iii)tribromide catalysts, mononuclear and dinuclear bismuth(iii)complexes of heavier chalcogenones are very active towards an acylative cleavage of cyclic ethers through a mild and regioselective strategy. In particular, mononuclear imidazolthione-bismuth(iii)trichloride is very active towards O-acylative cleavage of 2-methyl tetrahydrofuran. This journal is
- Srinivas, Katam,Suresh, Paladugu,Babu, Chatla Naga,Sathyanarayana, Arruri,Prabusankar, Ganesan
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p. 15579 - 15590
(2015/03/05)
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- An efficient iron catalyzed regioselective acylative cleavage of ethers: Scope and mechanism
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A method involving iron catalyzed acylative cleavage of cyclic and acyclic ethers with acyl/aroyl chlorides has been studied to produce chloroesters and esters respectively. Examination of the scope revealed that less electron rich alkyl group in unsymmetric, acyclic ether was acylated while the chloride derived from the counterpart moiety was volatile and difficult to isolate. In contrast, α-branched cyclic ethers were converted to the corresponding primary ester and secondary chloride. Steric hindrance of ether also plays an important role in acylative C-O bond cleavage. The mechanism of ether cleavage is proposed to involve a single electron initiated SN1 dissociative pathway.
- Bodduri, V.D. Vijaykumar,Choi, Kyung-Min,Vaidya, Raghavender Rao,Patil, Kalpesh,Chirumarry, Sridhar,Jang, Kiwan,Yoon, Yong-Jin,Falck, John R.,Shin, Dong-Soo
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supporting information
p. 7089 - 7093
(2015/12/01)
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- Control of sample alignment mode for hybrid lamellar systems based on gold nanoparticles
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New hybrid materials made of gold nanoparticles functionalized by mesogenic ligands form laminated smectic phases. Mechanical shearing produces macro size domains with uniformly oriented layers with the layer normal either perpendicular (perpendicular mode) or parallel (transverse mode) to the shearing direction. This is in contrast to low weight and polymer liquid crystals which usually show parallel mode of orientation. the Partner Organisations 2014.
- Wolska,Pociecha,Mieczkowski,Górecka
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supporting information
p. 7975 - 7978
(2014/07/08)
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- Side-chain liquid-crystalline polymer tetrazoles: Synthesis and characterization
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The synthesis and phase behavior of three new side-chain liquid crystal polymers with short and long flexible alkyl spacers are described. These new materials show smectic C (SmC) mesophase. X-ray analysis for two samples has revealed that SmC mesophase displays partial interdigitation for the polymer with short flexible spacer, while for long flexible spacer polymer no interdigitation was observed. ?2014 Sociedade Brasileira de Qui?mica.
- Tariq, Muhammad,Hameed, Shahid,Magnago, Rachel F.,Bechtold, Ivan H.,Merlo, Aloir A.
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p. 1275 - 1282
(2014/08/05)
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- Synthesis of δ- And ε-cyanoesters by zinc-catalyzed ring-opening of cyclic ethers with acid chlorides and subsequent cyanation
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In the present study, the zinc-catalyzed cleavage of cyclic ethers with acid halides as nucleophiles to yield chloroesters with different chain length has been investigated in detail. In the presence of straightforward and commercially available zinc salts as pre-catalysts excellent yields and selectivities were feasible. After studying the reaction conditions and the scope of the method, several efforts were carried out to understand the reaction mechanism. The obtained chloroesters were subsequently converted to δ- and ε-cyano esters, which are useful precursors in natural product synthesis. Graphical Abstract: [Figure not available: see fulltext.]
- Enthaler, Stephan,Weidauer, Maik
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experimental part
p. 168 - 175
(2012/03/27)
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- Use of magnesium (turnings) as a powerful catalyst for the o-acylative cleavage of tetrahydrofuran
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In a short reaction time, acyl chlorides and dry tetrahydrofuran react in the presence of a catalytic amount of magnesium turnings (Mg) at 25 °C to give 4-chlorobutyl esters in excellent yields. Copyright
- Pasha,Manjula, Krishnappa
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experimental part
p. 2309 - 2314
(2011/06/27)
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- Convenient synthesis of chlorohydrins from epoxides using zinc oxide: Application to 5,6-epoxysitosterol
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Efficient synthesis of protected and unprotected chlorohydrins has been achieved by ring opening of epoxides with acetyl/benzoyl chloride and TMSCl using a catalytic amount of ZnO as a reusable catalyst. The applicability of ZnO is further extended by performing the cleavage of the natural product 5,6-epoxysitosterol with acetyl chloride.
- Moghaddam, Firouz Matloubi,Saeidian, Hamdollah,Mirjafary, Zohreh,Javan, Marjan Jebeli,Farimani, Mehdi Moridi,Seirafi, Marjan
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scheme or table
p. 157 - 163
(2009/09/30)
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- Synthesis of chloroesters by the cleavage of cyclic and acyclic ethers using La(NO3)3·6H2O as a mild and efficient catalyst under solvent-free conditions
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A mild and an efficient synthesis of chloroesters is described by the reaction of cyclic and acyclic ethers with acid chlorides in the presence of a catalytic amount of La(NO3)3·6H2O under solvent-free conditions, affording the corresponding chloroesters in excellent yields. Copyright Taylor & Francis Group, LLC.
- Suresh,Suryakiran,Rajesh,Selvam, J. Jon Paul,Srinivasulu,Venkateswarlu
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- Simple and efficient method for the synthesis of δ-chloroesters from tetrahydrofuran and acyl chlorides in the presence of catalytic iodine
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Acyl chlorides and dry tetrahydrofuran (THF) in the presence of catalytic amounts of iodine at 25°C give δ-chloroesters in excellent yields. Copyright Taylor & Francis Group, LLC.
- Pasha,Manjula
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p. 927 - 932
(2007/10/03)
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- A mild and efficient synthesis of chloroesters by the cleavage of cyclic and acyclic ethers using Bi(NO3)3·5H2O as a catalyst under solvent-free conditions
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A facile, efficient synthesis of chloroesters is described. The reaction of cyclic and acyclic ethers with acid chlorides in the presence of catalytic amounts of Bi(NO3)2·5H2O under solvent-free conditions yielded the corresponding chloroesters. Also, the catalyst can be recovered conveniently and reused efficiently for at least six times.
- Suresh,Suryakiran,Venkateswarlu
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p. 1037 - 1040
(2008/09/16)
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- Scope and mechanism of the PdII-catalyzed arylation/carboalkoxylation of unactivated olefins with indoles
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Treatment of 1-methyl-2-(4-pentenyl)indole (5) with a catalytic amount of [PdCl2(MeCN)2] (2: 5 mol%) and a stoichiometric amount of CuCl2 (3 equiv) in methanol under CO (1 atm) at room temperature for 30 min gives methyl (9-methyl-2,3,4,9-tetrahydro-4-carhazolyl)acetale (6). which was isolated in 83% yield. A number of 2- and 3-alkenyl indoles undergo a similar palladium-catalyzed cyclization/carhoalkoxylation to give the corresponding polycyclic indole derivatives in moderate to excellent yields with excellent regio- and diaste reoselectivity. Under similar conditions, vinyl arenes undergo intermolecular arylation/carhoalkoxylation with indoles to give 3-(1-aryl-2-carbomethoxyethyl) indoles in moderate yield with high regioselectivity. Stereochemical analyses of the palladium-catalyzed cyclization/ carboalkoxylation of both 2- and 3-alkenyl indoles are in agreement with mechanisms involving outer-sphere attack of the indole on a palladiumolefin complex followed by α-migratory insertion of CO and methanolysis of the resulting acyl palladium intermediate. CuCl2 functions as the terminal oxidant in this palladium-catalyzed cyclization/carboalkoxylation of alkenyl indoles and also significantly increases the rate of reaction of 2 with the alkenyl indole to form the corresponding acyl palladium complex. Spectroscopic studies are in agreement with the intermediacy of a heterobimetallic Pd/Cu complex as the active catalyst in this reaction.
- Liu, Cong,Widenhoefer, Ross A.
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p. 2371 - 2382
(2008/02/03)
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- Mild and efficient method for the cleavage of cyclic and acyclic ethers by iodine under solvent-free conditions
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Ethers undergo smooth cleavage with acyl chlorides in the presence of a catalytic amount of elemental iodine under extremely mild conditions to give the corresponding halo esters. This new procedure offers significant advantages such as high conversions, short reaction times and enhanced selectivity together with mild reaction conditions, which makes it an attractive strategy.
- Yadav,Reddy,Reddy, P. Murali Krishna,Gupta, Manoj K.
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p. 8493 - 8495
(2007/10/03)
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- Bi(III) halides as efficient catalysts for the O-acylative cleavage of tetrahydrofurans: An expeditious entry to tetralins
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The mild (DCM/20°C), quantitative, regioselective, O-acylative cleavage of tetrahydrofurans using organic acid halides with catalytic Bi(III) halides is reported. X-ray crystallography is used to rationalise the failure of the reaction in the case of certain crowded acid chlorides, and a useful aspect of chemoselectivity is revealed. The synthetic potential of this reaction is illustrated with a highly efficient O-acylative cleavage/intramolecular alkylation approach to tetralins.
- Coles, Simon J.,Costello, James F.,Draffin, William N.,Hursthouse, Michael B.,Paver, Simon P.
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p. 4447 - 4452
(2007/10/03)
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- (Chloro-phenylthio-methylene)dimethylammonium chloride (CPMA) an efficient reagent for selective chlorination and bromination of primary alcohols
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(Chloro-phenylthio-methylene)dimethylammonium chloride reacts smoothly with a variety of alcohols, to afford the corresponding alkyl chloride in good yields. In the presence of tetrabuthylammonium bromide the corresponding bromide is obtained. Selective halogenation of primary hydroxyl groups in the presence of an unprotected secondary one is described. The mild reaction conditions involved are compatible with the major alcohol protecting groups as well as with acid sensitive functions like epoxides. (C) 2000 Elsevier Science Ltd.
- Gomez,Gellibert,Wagner,Mioskowski
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p. 6049 - 6052
(2007/10/03)
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- Organomercury/aluminum-mediated acylative cleavage of cyclic ethers
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Epoxides and tetrahydrofurans are cleaved with concomitant acylation to chloroalkyl esters using a reagent system composed of an organomercurial, aluminum metal and an acid chloride. The cleavage is promoted under mild conditions by a range of readily-available cyclic β-alkoxychloromercurials and acid chlorides. Using mainly tetrahydrofuran and cyclohexene oxide as substrates, the yield of isolated chloroesters ranged from 52 to 96%.
- Luzzio, Frederick A.,Bobb, Rhiana A.
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p. 1851 - 1858
(2007/10/03)
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- Formation, Stability, and Reactivity of Radical Cations of 1-Bromo-n-chloroalkanes in Aqueous Solution: A Pulse Radiolysis Study
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Hydroxyl radicals are able to form solute radical cations in acidic aqueous solutions of 1-bromo-n-chloroalkanes (n=1-6).Depending on the value of n, the bromine centered radical cation stabilizes on coordination with an unoxidized bromine atom from another molecule (intermolecular) or with an unoxidized chlorine atom of the same molecule (intramolecular).With n=2, 5, and 6, only dimer radical cations (λmax=430-450 nm) are formed through intermolecular coordination whereas, with n=1, 3, and 4, radical cations are stabilized both by intra- and intermolecular coordination, forming intramolecular radical cations (λmax=380 nm) or dimer radical cations (λmax=425-440 nm) at low and high solute concentrations, respectively.Cl2.- is unable to undergo an electron transfer reaction with 1-bromo-2-chloroethane whereas SO4.- is able to react with 1-bromo-2-chloroethane with a bimolecular rate constant of 8.3 * 106 dm3 mol-1 s-1.The dimer radical cation of 1-bromo-2-chloroethane is a strong one-electron oxidant and is able to undergo electron transfer reaction with a number of molecules with high rate constant values (109 dm3 mol-1 s-1).The dimer radical cation decays by a deprotonation mechanism, and the stability constant is determined to be 147 dm3 mol-1 at 25 deg C.Quantum chemical calculations of the strength of the three-electron bond between two heteroatoms at a semiempirical level with AMI parametrization show good correlation with experimental results.Good correlation, between experimantal results and theoretical calculations, is also observed for variation of the net atomic charge over bromine, the ionization potential (IP) of the molecule, and the difficulty of oxidation of various alkyl halides.
- Maity, D. K.,Mohan, H.,Chattopadhyay, S.,Mittal, J. P.
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p. 12195 - 12203
(2007/10/02)
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- Studies on organolanthanide complexes XXXVII. Reaction of dicyclopentadienylyttrium chloride with acyl chlorides in tetrahydrofuran. Acylative cleavage of the Cp-Y ?-bond and tetrahydrofuran ring
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Dicyclopentadienylyttrium chloride reacts with aromatic and aliphatic acid chlorides in tetrahydrofuran at room temperature, resulting in cleavage of the Cp-Y ?-bond to produce 1,5-diacylcyclopentadienes, and the acylative ring-opening of tetrahydrofuran.A possible reaction mechanism is proposed.
- Qian, Changtao,Qiu, Aineng,Huang, Yaozeng,Chen, Wenjie
-
-
- Cobalt(II)chloride catalysed cleavage of ethers with acyl halides: Scope and mechanism
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Cobalt(II) chloride in acetonitrile catalyses the cleavage of a wide variety of ethers with acyl halides under mild conditions to give the corresponding esters in good yields. Acyclic aliphatic ethers are cleaved to the corresponding ester and chlorides whereas the cyclic aliphatic ethers give rise to the ω-chloroesters. The benzyl ethers can be converted to the corresponding esters along with the formation of benzyl chloride and benzyl acetamide. A comparative study for the cleavage of allyl and benzyl ether has revealed that benzyl ether can be selectively cleaved in presence of the allyl ethers. The oxiranes can be cleaved in highly regioselective manner to the corresponding-β-chloroesters. The vinyl ethers undergo sp2-hybridised carbon-oxygen bond cleavage under these conditions. Based on product analysis, a mechanism involving electron transfer followed by O-acylation and S(N)1 or S(N)2 attack by chloride-ion is discussed.
- Iqbal,Srivastava
-
p. 3155 - 3170
(2007/10/02)
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- Non-Catalyzed Cleavage Reactions of Ethers with Acyl Halides under High-Pressure Conditions
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Various cyclic and acyclic ethers are efficiently cleaved with acyl chlorides or bromides to give ω-chloro- or ω-bromoesters under high-pressure conditions.
- Kotsuki, Hiyoshizo,Ichikawa, Yoshikatsu,Nishizawa, Hitoshi
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p. 673 - 676
(2007/10/02)
-
- MECHANISMS OF FREE-RADICAL REACTIONS. XXIV. QUANTITATIVE DESCRIPTION OF THE POLAR EFFECTS OF SUBSTITUENTS ON THE KINETICS OF THE FREE-RADICAL CHLORINATION OF ALIPHATIC COMPOUNDS BY N-CHLOROPIPERIDINE
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The free-radical chlorination of 1-substituted alkanes with electron-withdrawing substituents by N-chloropiperidine in trifluoroacetic acid was studied by the method of competing reactions, and the relative rate constants were obtained for all positions of the substrates.The data on the position selectivity can be described satisfactorily by means of an electrostatic model of the polar effect of the substituent, calculated according to the Kirkwood-Westheimer equation.The obtained characteristics of the electrostatic effect can be successfully applied to calculation of the substrate selectivity and the intermolecular relative rate constants for all the positions, beginning with the third.The Taft equation is unsuitable for description of the effect of substituents on the reaction rate.
- Dneprovskii, A. S.,Mil'tsov, S. A.,Arbuzov, P. V.
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p. 1826 - 1835
(2007/10/02)
-
- Cobalt(II) Chloride Catalysed Acylative Cleavage of Ethers
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In the presence of catalytic amount of cobalt(II) chloride in acetonitrile, a wide variety of ethers are cleaved with acyl chlorides, to the corresponding esters in good to excellent yield.
- Ahmad, Saeed,Iqbal, Javed
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p. 953 - 956
(2007/10/02)
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- Experimental evidence for AcO-7 neighboring group participation
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The reaction of diol diacetates with anhydrous aluminium chloride at ca 100° leads to displacement of only one of the acetoxy groups by chlorine. An oxygen-18 label study has shown that these displacements take place via acetoxonium intermediates and has provided direct evidence for the intervention of a seven-membered ring acetoxonium ion in the displacement of acetate by chlorine in 1,4-butanediol diacetate.
- Wilen, Samuel H.,Delguzzo, Luciano,Saferstein, Richard
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p. 5089 - 5094
(2007/10/02)
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- Novel omega-(N-imidazolyl)alkyl ethers of 1,2,3,5-tetrahydroimidazo[2,1-b]quinazolin-2-ones
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Novel compound wherein n is an integer of 1 to 8; R1 is hydrogen or alkyl of 1-6 carbons; R2 is hydrogen; R3 is hydrogen, alkyl of 1-6 carbons, phenyl, benzyl, hydroxy lower alkyl, carbamoyl alkyl, carboxyalkyl, alkoxycarbonylalkyl; R4 is hydrogen, alkyl of 1-6 carbons, benzyl, or hydroxy lower alkyl; Y is hydrogen, alkyl of 1 to 4 carbon atoms, halo or lower alkoxy; any of its optical isomers, the mixture thereof, or the pharmaceutically acceptable acid addition salt. These compounds are inhibitors of thromboxane synthetase and cyclic AMP phosphodiesterase and are therefore potential cardiovascular agents particularly useful as platelet aggregation inhibitors and anti-thrombotic agents. Accordingly, these compounds will preferably be useful in treating cardiovascular disorders with thrombotic complications. However, they also possess vasodilatory, antisecretory, antihypertensive, inotropic and antimetastatic activities.
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- Chlorination of Carboxylic Acid Derivatives. IX. Liquid Phase Chlorination of Aliphatic C2-C8 Alkyl Acetates. EI Mass Spectra of Monochlorinated Esters
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A series of aliphatic alkyl acetates from ethyl to octyl acetate was chlorinated in the liquid phase in order to obtain monochlorinated products.The chlorination of esters was carried out with chlorine in the liquid phase in the absence and in the presence of benzene and with sulfuryl chloride in the presence of Bz2O2.The products were determined by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry.Chlorination is appreciably deactivated at the 1-position, particularly with SO2Cl2, the deactivation at the 2-position being strongest with Cl2 in the presence of benzene.The amounts of 1-chloro and ω-chloro isomers constituted the greatest disparity between the chlorination methods.The most characteristic mass spectral fragment ions of the 35 chlorinated alkyl acetates are given.
- Korhonen, Ilpo O. O.
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- Studies on the Occurence of Hydrogen Transfer, 67. Enediol Diesters by Acylating Electroreductive Dimerization of Acyl Chlorides with Lithium Amalgam
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Aromatic, aliphatic, and aromatic-aliphatic acyl chlorides (and anhydrides) are transformed by lithium amalgam (Li/Hg) to cis- and/or trans enediol diesters 1-10 (acylating reductive dimerization), mostly in ca. 70percent yields.The influence of the solvent on the reaction course is investigated.Starting from 2,2'-biphenyldicarbonyl dichloride, the phenanthrene 7 is formed; phthalide 8 is the reaction-product using phthaloyl dichloride as starting material.Diphenylphosphinyl chloride is reduced by Li/Hg to tetraphenyldiphosphane dioxide (15).A reaction mechanism for the acylating reductive dimerization is proposed on the basis of the halve-wave potentials determined for 12 acyl chlorides and four 1,2-diketones.The latter are intermediates in the acylating reductive dimerization of the acyl chlorides.Enediol diesters are obtained starting from 1,2-diketones and Li/Hg in the presence of acyl chlorides.Trimethylsilyl chloride is unsuitable as a trap for the enediols; it is preferentially reduced at the Li/Hg interface.Tetrahydrofuran as solvent is transformed to RC(O)O-4-Cl by a known ring-opening acylation reaction in the presence of Lewis acids (LiCl or ZnCl2) formed by the decomposition of Li/Hg and Zn/Hg.
- Horner, Leopold,Dickerhof, Karlheinz
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p. 1603 - 1614
(2007/10/02)
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- Acylative Cleavage of Ethers Catalyzed by Triorganotin Halides and Palladium(II) Complexes
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Benzylic, allylic, and cyclic ethers react with acyl halides under mild conditions in the presence of triorganotin halide and palladium(II) catalysts to give the corresponding esters in good yields.In the case of benzyl ether the other product is the benzyl halide, while in the reaction of allylic ethers the other products are various olefins resulting from the cleavage of the allyl group and an organotin moiety.The reaction is selective to these ethers, while acyclic aliphatic and phenolic ethers are unreactive.By control of the reaction conditions, benzylic andcyclic ethers could be cleaved in the presence of allylic ethers.The utility of the reaction as a deprotective method is demonstrated by the cleavage of a benzylic ether containing olefinic unsaturation.The mechanism of the benzylic and allylic ethers cleavage was studied by carrying out the corresponding stoichiometric reactions with the various palladium(II) complexes proposed in the catalytic cycle.
- Pri-Bar, I.,Stille, J. K.
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p. 1215 - 1220
(2007/10/02)
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