- (η6-Arene) ruthenium(ii) complexes and metallo-papain hybrid as Lewis acid catalysts of Diels-Alder reaction in water
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Covalent embedding of a (η6-arene) ruthenium(ii) complex into the protein papain gives rise to a metalloenzyme displaying a catalytic efficiency for a Lewis acid-mediated catalysed Diels-Alder reaction enhanced by two orders of magnitude in water.
- Talbi, Barisa,Haquette, Pierre,Martel, Annie,De Montigny, Frederic,Fosse, Celine,Cordier, Stephane,Roisnel, Thierry,Jaouen, Gerard,Salmain, Michele
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- Diels-Alder reactions in room-temperature ionic liquids
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The Diels-Alder cycloaddition reaction between methyl acrylate and cyclopentadiene has been investigated in a number of air and moisture stable ionic liquids. The endo/exo ratio of the reaction has been used as an initial probe of the nature of the solvents.
- Fischer,Sethi,Welton,Woolf
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- Combining in situ FTIR spectroscopy, BTEM analysis, bulk density measurements and DFT for two Diels-Alder reactions. A general approach for partial molar volume and reaction volume analyses
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Two organic reactions, namely the reaction of cyclopentadiene (CPD) and dimethyl acetylene dicarboxylate (DMAD) and the dimerization reaction of CPD were conducted in toluene at 298.1 K at atmospheric pressure and measured by in situ FTIR spectroscopy. Band-target entropy minimization (BTEM) analyses were employed for obtaining the pure component spectra of the solutes and their corresponding concentrations. The solute concentrations and the bulk density data were used to evaluate the partial molar volumes of the solute constituents. The partial molar volumes evaluated from this multi-component approach were in good agreement with those determined from independent binary solution measurements. The corresponding volumes of reaction for the CPD + DMAD and dimerization CPD + CPD reactions were determined to be -37 ± 3 cm 3 mol-1 and -31 ± 2 cm3 mol -1, respectively. For completeness, DFT calculations were performed and used to rationalize the vibration modes corresponding to the BTEM spectral estimates as well as to provide predictions of the molar volumes of the solutes. The present study demonstrates the usefulness of a combined spectroscopic, signal processing, bulk density measurement and DFT approach to the determination of partial molar volumes and volumes of reaction directly from the multi-component reactive systems. This journal is the Partner Organisations 2014.
- Tjahjono, A. Martin,Feng, Gao,Hermanto, Martin Wijaya,Cechao, Foo,Garland, Marc
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- Regioselective thermal cage-opening reactions of 4-amino substituted 1,3-bishomocubanones
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Thermolysis of 4-substituted 1,3-bishomocubanones is strongly dependent on the electronic nature of the bridgehead substituent. 4-(N-benzyl)amido- substituted cage compounds 12 unexpectedly furnish bicyclic annelated cyclopentenones 13, whereas the 4-acet
- Bakkeren, Frank J.A.D.,Schroeer, Frank,Klunder, Antonius J.H.,Zwanenburg, Binne
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- Rhodium catalyzed one-step hydroamidation of cyclopentadiene and dicyclopentadiene
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A one-step rhodium catalyzed direct route from alkene to amide is presented via the hydroamidation reaction of cyclopentadiene and dicyclopentadiene with pyrrolidine. A homogeneous catalyst of [Rh(cod)Cl]2 without additional phosphorus ligands was established giving a 90% yield of the respective monoamide species of Dcpd with a high TOF of 1060 h-1. An important side reaction in hydroamidation reactions is the formation of oligomers of dicyclopentadiene. This unwanted reaction could be overcome by the optimum adjustment of the olefin/amine ratio. The desired atom economic hydroamidation, which uses the inexpensive bulk chemicals carbon monoxide and dicyclopentadiene, could be scaled up to a multigram scale with comparable catalyst activity.
- Behr, Arno,Levikov, Denys,Nürenberg, Edward
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- Application of hierarchical pore molecular sieve in preparation process of cyclopentadiene and JP-10 aviation fuel
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The invention relates to an application of a hierarchical pore molecular sieve in a the preparation process of cyclopentadiene and JP-10 aviation fuel. The hierarchical pore molecular sieve is one or two or more of an H-ZSM-5 molecular sieve, an H-beta molecular sieve, an H-Y molecular sieve, an H-USY molecular sieve, a La-Y molecular sieve and an H-MOR molecular sieve with a hierarchical pore structure, a sulfonated SBA-15 molecular sieve, a sulfonated MCM-41 molecular sieve, a sulfonated Ti-SBA-15 molecular sieve, a sulfonated MCM-41 molecular sieve, a sulfonated Zr-MCM-41 molecular sieve and a sulfonated Zr-SBA-15 molecular sieve; and the hierarchical pore structure comprises micropores and mesopores. The catalyst and the raw materials used in the method are cheap and easy to obtain, the preparation process is simple, and the hierarchical pore molecular sieve has high activity and selectivity for rearrangement reaction of furfuryl alcohol, hydrogenation reaction of hydroxyl cyclopentenone and dehydration reaction. The invention provides a cheap and efficient synthesis method for synthesizing the JP-10 aviation fuel from a lignocellulose-based platform compound furfuryl alcohol.
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Paragraph 0023; 0121-0126
(2021/07/01)
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- Cyclopentadiene fuels
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A method for making cyclopentadiene fuels comprising producing cyclopent-2-en-1-one or a mixture of cyclopent-2-en-1-one from a bio-based source. The cyclopent-2-en-1-one or the mixture of cyclopent-2-en-1-one is hydrogenated, thereby forming cyclopent-2-en-1-ol or a mixture of cyclopent-2-en-1-ol. The cyclopent-2-en-1-ol or the mixture of cyclopent-2-en-1-ol is dehydrated with a dehydrating agent, thereby forming cyclopentadiene or a mixture of cyclopentadiene. The cyclopentadiene or mixture of cyclopentadiene is converted to dicyclopentadiene or dihydrodicyclopentadiene. The dicyclopentadiene or dihydrodicyclopentadiene is hydrogenated, thereby forming tetrahydrodicyclopentadiene. The tetrahydrodicyclopentadiene is isomerized, thereby forming exo-tetrahydrodicyclopentadiene.
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Page/Page column 7
(2021/08/04)
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- Method for Production of 5-Vinyl-2-Norbornene Using Porous Titanosilicate Catalyst
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The present invention relates to a method for manufacturing 5-vinyl-2-norbornene (VNB) by conducting reaction of cyclopentadiene (CPD) with 1,3-butadiene (BD). The method uses a porous titanosilicate catalyst, thereby providing an effect of increasing the selectivity of VNB and reducing the selectivity of by-product oligomer.(AA) CPD conversion ratio (%)(BB) VNB selectivity (%)(CC) THI selectivity (%)(DD) DCPD selectivity (%)(EE) Oligomer selectivity (%)(FF) Conversion ratio and selectivity (%)COPYRIGHT KIPO 2020
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Paragraph 0036-0040; 0045-0046
(2020/09/10)
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- Making JP-10 Superfuel Affordable with a Lignocellulosic Platform Compound
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The synthesis of renewable jet fuel from lignocellulosic platform compounds has drawn a lot of attention in recent years. So far, most work has concentrated on the production of conventional jet fuels. JP-10 is an advanced jet fuel currently obtained from fossil energy. Due to its excellent properties, JP-10 has been widely used in military aircraft. However, the high price and low availability limit its application in civil aviation. Here, we report a new strategy for the synthesis of bio-JP-10 fuel from furfuryl alcohol that is produced on an industrial scale from agricultural and forestry residues. Under the optimized conditions, bio-JP-10 fuel was produced with high overall carbon yields (≈65 %). A preliminary economic analysis indicates that the price of bio-JP-10 fuel can be greatly decreased from ≈7091 US$/ton (by fossil route) to less than 5600 US$/ton using our new strategy. This work makes the practical application of bio-JP-10 fuel forseeable.
- Li, Guangyi,Hou, Baolin,Wang, Aiqin,Xin, Xuliang,Cong, Yu,Wang, Xiaodong,Li, Ning,Zhang, Tao
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p. 12154 - 12158
(2019/08/12)
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- Method for preparing JP-10 aviation fuel from furfuryl alcohol
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The invention relates to a method for preparing JP-10 aviation fuel from furfuryl alcohol. The method for preparing JP-10 aviation fuel by taking the furfuryl alcohol as a raw material is totally divided into six reactions as follows: a first reaction of carrying out a rearrangement reaction on a furfuryl alcohol solution in the presence of a base catalyst or under the condition that any catalystis not added to prepare hydroxy cyclopentenone; a second reaction of reacting the hydroxy cyclopentenone and hydrogen under catalysis of a hydrogenation catalyst so as to prepare 1,3-cyclopendiol; a third reaction of dehydrating the 1,3-cyclopendiol to prepare cyclopentadiene; a fourth reaction of carrying out a D-A reaction on the cyclopentadiene to produce dicyclopentadiene; a fifth reaction ofhydrogenating the dicyclopentadiene to produce endo-tetrahydrodicyclotadiene; and a sixth reaction of performing isomerization on the endo-tetrahydrodicyclotadiene to produce hanging type tetrahydrodicyclopentadiene, wherein the prepared hanging type tetrahydrodicyclopentadiene can directly serve as the JP-10 aviation fuel. The invention provides a cheap high-efficiency synthetic method for synthesizing the JP-10 aviation fuel from a lignocelluloses-based platform chemical compound, namely furfuryl alcohol.
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Paragraph 0129; 0130; 0132
(2018/06/16)
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- Method for preparing JP-10 aviation fuel from furfuryl alcohol
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The invention relates to a method for preparing JP-10 aviation fuel from furfuryl alcohol. The method for preparing the JP-10 aviation fuel by adopting the furfuryl alcohol as a raw material comprises the following five steps: step I, enabling a furfuryl alcohol solution to have a rearrangement reaction to prepare hydroxylcyclopentenone under the condition of an alkaline catalyst or no catalyst; step II, enabling the hydroxylcyclopentenone to react with hydrogen under the catalysis of a hydrogenation catalyst to prepare 1,3-cyclopentanediol; step III, preparing cyclopentadiene or dicyclopentadiene by dehydrating the 1,3-cyclopentanediol; step IV, enabling the cyclopentadiene and the dicyclopentadiene to have an isomerization reaction to generate hanging dicyclopentadiene; and step V, hydrogenating the hanging dicyclopentadiene to generate hanging tetrahydro-dicyclopentadiene, and then rectifying and purifying to obtain the JP-10 aviation fuel. Raw materials used in the method are cheap and easy to obtain, the preparation process is simple, and the activity and selectivity for the rearrangement reaction of the furfuryl alcohol, the hydrogenation reaction of the hydrocyclopentenone and the dehydration reaction is relatively high. The invention provides a synthetic method with low cost and high efficiency for synthesizing the cyclopentadiene or the dicyclopentadiene from lignocelluloses-based platform compound and furfuryl alcohol.
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Paragraph 0102; 0103; 0104; 0105; 0106; 0107-0117
(2017/07/21)
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- Method for preparation of cyclopentadiene or dicyclopentadiene by furfuryl alcohol
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The invention relates to a method for preparation of cyclopentadiene or dicyclopentadiene by furfuryl alcohol. The method for preparation of cyclopentadiene or dicyclopentadiene by furfuryl alcohol as a raw material comprises the three-step reaction: a first step, under a condition with an alkali catalyst or under a condition with no addition of a catalyst, carrying out a rearrangement reaction of a furfuryl alcohol solution to prepare hydroxy cyclopentenone; a second step, under catalysis of a hydrogenation catalyst, carrying out a reaction of hydroxy cyclopentenone with hydrogen gas to prepare 1,3-cyclopendiol; and a third step, dehydrating 1,3-cyclopendiol to prepare cyclopentadiene or dicyclopentadiene. The used catalyst and raw materials are inexpensive and easy to obtain, the preparation process is simple, and high activity and selectivity are achieved for rearrangement reaction of furfuryl alcohol, hydrogenation reaction of hydroxy cyclopentenone and dehydration reaction of 1,3-cyclopendiol. The invention provides the cheap and efficient synthesis method for synthesis of cyclopentadiene or dicyclopentadiene with the lignocellulose based platform compound furfuryl alcohol.
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- Preparation method of exo-form compound from endo-form compound using metal organic framework catalyst
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The present invention relates to a method for manufacturing an exo-type compound from an endo-type compound using a metal organic framework catalyst. More particularly, the manufacturing method for manufacturing an exo-type compound comprises a step of performing an isomerization reaction of an endo-type compound to form an exo-type compound in the presence of a metal organic framework. The metal organic framework exhibits acidity, and has pores which can accommodate molecules having a longest diameter of at least 6andAring;. The catalyst can exhibit an excellent conversion rate from endo-dicyclopentadiene to exo-dicyclopentadiene without using a solvent through a simple and efficient process.COPYRIGHT KIPO 2016
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Paragraph 0053-0062
(2017/04/03)
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- Catalytic performance of MIL-100 (Fe, Cr) and MIL-101 (Fe, Cr) in the isomerization of endo- to exo-dicyclopentadiene
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MIL-100 (Fe, Cr) and MIL-101 (Fe, Cr), metal-organic frameworks (MOFs), have been assessed in solvent-free isomerization of dicyclopentadiene (DCPD) from the endo- to exo-form. In the isomerization reaction, the conversion of endo-DCPD and selectivity for the exo-dimer strongly depend on the nature of the active metal center. The MIL-100 (Fe) catalyst possessing more acid sites shows the highest catalytic activity among the MILs and it was readily recoverable and reusable in subsequent reaction cycles for the isomerization. The effects of reaction parameters such as temperature, reaction time, and catalyst loading on the reactivity were also investigated.
- Kim, Dong-Woo,Kim, Hyeon-Gook,Cho, Deug-Hee
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- 5-ethylidene-2-norborene ENB method for the production of (by machine translation)
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The invention relates to a production method for ENB (5-ethylene-2-norbornylene) and mainly aims to solve the problems in the prior art that the purity of a product is low and the energy consumption is high. The adopted production method for the ENB comprises the following steps: (1) raw materials and a solvent are sent to a first reaction vessel through a static mixer; (2) the reaction product in the first reaction vessel enters into a light component removing tower, tower top light components return to the first reaction vessel and tower kettle heavy components enter into a heavy component removing tower; (3) the kettle components of the heavy component removing tower enter into a DCPD tower, and tower top distilled liquid is purified to obtain a DCPD product; (4) the heavy component removing tower kettle components enter into a VCH tower, the VCH is obtained at the tower top; tower kettle components enter into a VNB tower, THI is obtained in a VNB tower kettle and the VNB is obtained at the tower top; (5) VNB enters into an isomerization reaction vessel to obtain ENB. The problems are better solved by the technical scheme and the production method can be applied in the ENB production.
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Paragraph 0020-0026
(2017/05/26)
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- PROCESS FOR TREATING A DICYCLOPENTADIENE MONOMER
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A monomer treatment process including treating at least one metathesis polymerizable monomer composition having a purity of less than 95 weight percent of a dicyclopentadiene monomer with an alkali metal-containing additive prior to polymerizing the metathesis polymerizable monomer composition such that the treated polymerized monomer exhibits improved properties in metathesis reactions.
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(2015/05/26)
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- Bifunctional lactide monomer derivative and polymers and materials prepared using the same
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The invention described herein provides a novel lactide monomer derivative and process for preparing the lactide monomer derivative. The monomer derivative of the invention is bifunctional in nature, and can be employed a variety of efficient synthesis processes to prepare various polymers. Further, the bifunctional monomer derivative can be used to prepare various intermediate-stage compounds and polymers, which in turn can be used to synthesize other compounds, polymers, copolymers and composites. The lactide monomer derivative has a bifunctional norbornene spiro lactide structure, spiro[6-methyl-1,4-dioxane-2,5-dione-3,2′-bicyclo[2.2.1]hept[5]ene], and structure as follows: and stereoisomers thereof. The lactide monomer derivative is bifunctional in that either 1) the norbornene ring, 2) lactide ring, or 3) both, can be opened and used in polymer synthesis for the backbone or the reactive branch for other polymeric syntheses.
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(2012/06/30)
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- Micellar-driven substrate selectivity in Cr(salen)Cl catalytic Diels-Alder reaction in water
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A 3.5 increase in catalytic activity was observed in the Cr(III) (salen)Cl 3 catalyzed Diels-Alder reaction between cyclopentadiene 1 with the longer trans-2-decenal 2g compared to the shorter trans-2-butenal 2a dienophile under aqueous micellar conditions, while in chloroform the two substrates react with comparable activities.
- Trentin, Francesco,Scarso, Alessandro,Strukul, Giorgio
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supporting information; experimental part
p. 6978 - 6981
(2012/02/13)
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- Mechanochemical Diels-Alder cycloaddition reactions for straightforward synthesis of endo-norbornene derivatives
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Under mechanochemical milling conditions, Diels-Alder cycloaddition of cyclopentadiene with maleic anhydride and maleimide derivatives proceeded very smoothly, affording endo-norbornenes exclusively in quantitative yield. All the transformations were accomplished at room temperature without using any catalyst or organic solvent, thus the workup and purification procedure is very simple. Control experiments on traditional and other tentative conditions were also investigated. Georg Thieme Verlag Stuttgart - New York.
- Zhang, Ze,Peng, Zhi-Wei,Hao, Ming-Feng,Gao, Jian-Gang
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scheme or table
p. 2895 - 2898
(2011/02/23)
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- Newtonian kinetic isotope effects. Observation, prediction, and origin of heavy-atom dynamic isotope effects
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(Figure Presented) Intramolecular 13C kinetic isotope effectswere determined for the dimerization of cyclopentadiene. Substantial is otope effects were observed in three positions, despite the C2 symmetry of the cycloaddition transition state and the absence of dynamical bottlenecks after this transition state. The observed isotope effects were predicted well from trajectory studies by extrapolating the outcomes of trajectories incorporating superheavy isotopes of carbon, ranging from 20C to 140C. Trajectory studies suggest that the isotope effects are unrelated to zero-point energy or the geometrical and momentum properties of the transition state. However, steepestdescent paths in mass-weighted coordinates correctly predict the direction of the isotope effects, supporting a novel origin in Newton's second law of motion.
- Kelly, Kelmara K.,Hirschi, Jennifer S.,Singleton, Daniel A.
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supporting information; experimental part
p. 8382 - 8383
(2009/10/23)
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- PROCESS FOR PRODUCING HIGH PURITY EXO-ALKENYLNORBORNENE
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Embodiments of the present invention are directed generally to methods for producing high purity exo-alkenylnorbornenes from a mixture of conformational isomers thereof.
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Page/Page column 17-20
(2009/07/02)
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- A route to enantiomerically pure 5-(2′-hydroxyethyl)cyclopent-2-en-1-ol and its absolute configuration by Mosher esters
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The (±)-5-(2′-hydroxyethyl)cyclopent-2-en-1-ol 1 was prepared in a one-pot procedure, and was resolved using lipase AK and vinyl acetate with high ee. This provides a readily available chiral synthon for the synthesis of a wide variety of biologically int
- Chen, Hao,Nagabandi, Srinivas,Smith, Steven,Goodman, Jonathan M.,Plettner, Erika
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experimental part
p. 449 - 456
(2009/09/06)
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- POLYMERIZABLE CHEMILUMINESCENT COMPOUNDS
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Disclosed are compounds having the formula: wherein R1 is selected from the group consisting of hydrogen, C1-C6 alkyl, amino, N-C1-C6-alkylamino, and N,N—C1-C6-dialkylamino; and ring “A” is selected from the group consisting of unsubstituted or substituted C4-C8-cycloalkenyl, unsubstituted or substituted bicyclo [2,2,1]alkenyl, and unsubstituted or substituted bicyclo [2,2,2]alkenyl, unsubstituted phenyl, and phenyl substituted with a moiety selected from the group consisting of C3-C6-alkenyl, acryl, acryl-C1-C6 alkyl, acrylamido, and acrylamido-C1-C6 alkyl; polymers made from these compounds, and ELISAs that use the compounds and polymers as a chemiluminescent detection label.
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- Cyclopentadiene: The impact of storage conditions on thermal stability
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The potential hazards from cyclopentadiene storage and use on kilogram scale are studied under adiabatic conditions. Cyclopentadiene, a reagent commonly used in organic synthesis, is known to spontaneously dimerize exothermically and thus should be stored cold and used quickly. In the present work we consider the impact of storage conditions such as the container size, volume, temperature, and solvent dilution to assess the potentiel hazards of a runaway reaction. The results of this analysis clearly show that the hazards are significantly increased as the mass of cyclopentadiene being stored is increased.
- Amende, David J.,Whritenour, David C.,Coe, Jotham W.
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p. 1141 - 1146
(2012/12/30)
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- Latent, high-activity olefin metathesis catalysts containing an N-heterocyclic carbene ligand
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The invention provides novel organometallic complexes useful as olefin metathesis catalysts. The complexes have an N-heterocyclic carbene ligand and a chelating carbene ligand associated with a Group 8 transition metal center. The molecular structure of the complexes can be altered so as to provide a substantial latency period. The complexes are particularly useful in catalyzing ring closing metathesis of acyclic olefins and ring opening metathesis polymerization of cyclic olefins.
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- Thermal cracking of Diels-Alder adducts
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A method for thermally cracking Diels-Alder adducts and for altering organic streams containing Diels-Alder adducts using controlled cavitation conditions.
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- New approaches to syntheses of diethers and haloethers from cyclopentadiene
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Cyclopentadiene (CPD) is oxidized by copper(II) bromide and chloride in alcohol solutions to form dialkoxy- and haloethers and exhibits a higher reactivity than butadiene. Dialkoxy-, chloroalkoxy-, and dichlorocyclopentenes are formed from CPD and CuCl2 w
- Skumov, M. Ya.,Brailovskii, S. M.,Temkin, O. N.
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p. 616 - 624
(2007/10/03)
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- Diolefin/hydroxyaryl condensates and catalyst therefor
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A catalyst composition comprising trifluoromethanesulfonic acid (also referred to as triflic acid) and a sufficient quantity of a substance (also referred to as a retarder) to decrease but not eliminate the catalytic activity of the acid is disclosed. Also disclosed, is a method and composition for condensing a hydroxyaryl with a diene by use of the catalyst composition. The method is capable of producing condensates having: a mole ratio of 1 mole of the diene to one mole of the hydroxyaryl; one mole of diene to two moles of the hydroxyaryl as well as higher molecular weight products such as resins by changes in temperature, time of reaction, type and quantity of retarder and other variables.
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- Tetramethyldiamidophosphoric acid chloride mediated epoxide-diene conversion and steroidal aromatization
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The reaction of tetramethyldiamidophosphoric acid chloride with epoxides in the presence of a trace amount of water furnished 1,3-dienes in good yield. The conversion works with open chain and cyclic epoxides. A C-C bond cleavage reaction occurs if the epoxide contains a quaternary carbon. Application of this method to epoxy sterols afforded ring A aromatic steroids in good yield. The aromatization works via dienol-benzene rearrangements and is independent of the C-3 stereochemistry.
- Demir, Ayhan S
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p. 227 - 233
(2007/10/03)
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- Thermal rearrangement of 7-methylbicyclo[3.2.0]hept-2-ene: An experimental probe of the extent of orbital symmetry control in the [1,3] sigmatropic rearrangement
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The gas-phase thermal rearrangement of exo-7-methylbicyclo[3.2.0]hept-2-ene yields almost exclusively 5-methylnorbornene products. Inversion (i) of configuration dominates this [1,3] sigmatropic shift although some retention (r) is also observed. Because the [1,3] migration can only occur suprafacially (s) in this geometrically constrained system, the si/sr ratio of 7 observed for the migration of C7 in exo-7-methylbicyclo[3.2.0]hept-2-ene indicates that the orbital symmetry rules are somewhat permissive for the [1,3] sigmatropic migration of carbon.
- Bender, Jared D.,Leber, Phyllis A.,Lirio, Ruel R.,Smith, Randall S.
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p. 5396 - 5402
(2007/10/03)
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- Acceleration of Bimolecular Reactions by Solvent Viscosity
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We report the first example of acceleration of a bimolecular reaction by increased solvent viscosity. In a series of hydrocarbon solvents of graded viscosity, the rates of two cycloadditions, the Diels-Alder dimerization of cyclopentadiene and the 1,3-dipolar cycloaddition of diphenyldiazomethane with ethyl phenylpropiolate, rise with increasing viscosity to about 1 cP and then fall thereafter. We interpret this rise as viscosity-induced acceleration up to ~1 cP, which cannot be accounted for by current kinetic theory. Several examples from the literature are reinterpreted in these terms, providing further support for our concept.
- Swiss, Kevin A.,Firestone, Raymond A.
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p. 5369 - 5372
(2007/10/03)
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- Rearrangement and Cycloreversion of Diels-Alder Adducts of Cyclic 1,3-Dienes to Norbornadienes. A Novel homo-Cope Rearrangement. Evidence for Competitive Pericyclic and Diradical Processes
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On thermolysis of endo,endo-5, endo,endo-17, and endo,exo-17 ( the endo,endo and endo,exo Diels-Alder adducts of cyclopentadiene 7 or dimethylfulvene 15 to norbornadiene 8 or 7-isopropylidenenorbornadiene 20), a novel type of homo-Cope rearrangement leading to 6, 21, and 23a, respectively, competes with the retro-Diels-Alder reactions.According to a force-field analysis of the kinetic parameters, the competitive reactions (rearrangement and retro-Diels-Alder reaction) of endo,endo-5 occur in a pericyclic fashion whereas in the isopropylidene-substituted systems stepwise processes compete with the corresponding pericyclic reactions.Indirect experimental evidence for this assumption comes from a stereochemical analysis of the retro-Diels-Alder reaction in the cis-5,6-dideuterionorbornene derivatives exo-36-d2, endo-36-d2 and exo-39-d2, endo-39-d2 occuring stereospecifically in the case of exo-36-d2, endo-36-d2 and non-stereospecifically in the case of exo-39-d2, endo-39-d2.The change in mechanism rationalized by a different (allyl vs. pentadienyl) stabilization of the potential diradical intermediates in the stepwise reactions. - Key Words: Kinetic parameters / Stepwise and pericyclic reactions / Calculations, force field / Calculations of transition-state resonance energy (energy of concert)
- Hochstrate, Dirk,Klaerner, Frank-Gerrit
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p. 745 - 754
(2007/10/02)
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- Unsaturated imide compounds containing alicyclic structure, process for producing the same and intermediate therefor
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An unsaturated imide compound represented by formula (1): STR1 wherein Q is an alicyclic structure-containing hydrocarbon group having 4-20 carbon atoms; each of R1, R2, R3, R4, Ri and Rj represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1-6 carbon atoms or a halogen-containing hydrocarbon group having 1-6 carbon atoms; each of a, b, c, d, e and f represents an integer of 0 to 4 satisfying a+b≤4, c+d≤4 and e+f≤4 and D represents a divalent organic group having 2-24 carbon atoms and an ethylenically unsaturated double bond, a process for producing the unsaturated imide compound of formula (1) and intermediates for producing the unsaturated imide compound of formula (1). The unsaturated imide compound of formula (1) is well soluble in organic solvents and can give cured products excellent in heat resistance, low water absorption and flexibility.
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- Effect of micellar medium on photoannelation vs energy transfer in the system excited cyclohex-2-en-1-one-cyclopentadiene
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The relative ratio of enone-CPD adducts and C15H18 formed in the photochemical reaction between cyclohex-2-en-1-one and its 4,4 dimethyl derivative and CPD in different media suggest that an exciplex is responsible for 2+2 photoannelation and energy transfer and a transoid or twisted enone for photo Diels-Alder reaction.
- Kumar, M. Suresh,Rao, Jampani Madhusudana
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p. 5383 - 5388
(2007/10/02)
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- Liquid dicyclopentadiene feedstock for bulk polymerization
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Liquid dicyclopentadiene feedstocks are provided for bulk polymerization by the addition of reactive norbornene function containing cycloolefin monomers to solid, high purity dicyclopentadiene compositions. These liquid dicyclopentadiene feedstocks provide a high degree of conversion to polymer under bulk polymerization conditions.
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- A DIASTEREOSELECTIVE PREPARATION OF 7-ETHYL-7-METHYLBICYCLOHEPT-2-EN-6-ONE (1)
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Alkylation of 7-endo-ethylbicyclohept-2-en-6-one (2a) and 7-endo-methylbicyclohept-2-en-6-one (2b) with lithium diisopropylamide (LDA) and the appropriate alkyl iodide (methyl and ethyl iodide, respectively) afforded the title compound such that alkylation had occured exclusively on the exo face of the bicyclo system.
- Glass, Timothy E.,Klein, Susan J.,Leber, Phyllis A.
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p. 3553 - 3560
(2007/10/02)
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- The Kinetic Effects of Water and of Cyclodextrins on Diels-Alder Reactions. Host-Guest Chemistry. Part 18
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The rates of 19 different dienophiles with mostly cyclopentadiene have been measured in a range of solvents.Water, by comparison with methanol, is found to accelerate the cycloadditions by factors ranging from 15-7 680.While there is no simple correlation of the rate enhancement with the hydrophobicity of the substrates, a correlation can be made in the case of acrylates, which show a decreasing rate effect due to water, and with β-cyclodextrin, which is found to lead to inhibition in these and several other cases.Computer analysis of enzyme-like saturation kinetics-observed with some fumarates in the presence of β-cyclodextrin-indicates apparent binding constants for the ternary complex of ca. 102 dm3 mol-1 and catalytic kcat/ko ratios of up to 100.Heptakis-6 piperidino-β-cyclodextrin in the form of its ammonium salt leads to rate retardation in most of the cases investigated; sodium dodecylsulphate also decreases the constants. α-Cyclodextrin generates small effects, rate retardation, or in one case complete inhibition.
- Sangwan, Naresh K.,Schneider, Hans-Joerg
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p. 1223 - 1228
(2007/10/02)
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- Norbornadiene derivatives
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Novel compounds of the general formula:- in which each of R1 and R2 independently represents a hydrogen atom or an alkyl, cycloalkyl or aryl group; n is 0 or an integer from 1 to 4; and A is an optionally substituted propenyl formate group of the general formula: in which R3 is a hydrogen atom or an alkyl, cycloalkyl or aryl group; and each of R4 and R5 independently represents a hydrogen atom or an alkyl, cycloalkyl or aryl group, or R4 and R5 together represent an alkylene chain; are useful chemical intermediates. They may be converted by an internal hydrogenolysis reaction into known norbornene derivatives.
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- ORGANOTINS AS ETHERIFICATION CATALYSTS. III. ETHERIFICATIONS AND HYDRO-HYDROXY-ELIMINATIONS PROMOTED BY BUTYLTIN TRICHLORIDE
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Butyltin trichloride, as a catalyst precursor, promotes the following processes: (i) etherification of 2,3-unsaturated alcohols, (ii) etherification of functional diols, (iii) cyclization of 2,5-hexanedione, and (iv) dehydration of cyclic diols.Many examples are reported.
- Marton, Daniele,Slaviero, Pierangelo,Tagliavini, Giuseppe
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p. 7099 - 7108
(2007/10/02)
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- DIENOPHILIE DES OLEFINES CAPTODATIVES - VI SYNTHESES ET CYCLOADDITIONS DE DIELS-ALDER DES α-ALKYLTHIO-ACRYLATES D'ALKYLE AVEC LE CYCLOPENTADIENE: INFLUENCE DES FACTEURS STERIQUES SUR LA REACTIVITE ET SUR LA STEREOSELECTIVITE
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The Diels-Alder reactions of cyclopentadiene with a series of four α-alkylthio-alkyl acrylates were investigated.Although slightly slower than the reactions of unsubstituted alkyl acrylates, the spontaneous cycloadditions of these captodative olefins occur at room temperature affording adducts in excellent yield.The steric effect of the ester function is found to be more important in determining the dienophilic reactivity than the endo/exo ratios of the adducts and increase in the size of the alkylthio group reduces the endo selectivity of that group from 66-69percent (for methylthio) to 25-22percent (for tertiobutylthio group).The aluminium trichloride complexed methoxycarbonyl group leads to a very high endo-stereoselectivity (97percent) of that group.
- Boucher, Jean-Luc,Stella, Lucien
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p. 3595 - 3606
(2007/10/02)
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- Diastereoselectivity in the Diels-Alder Reactions of Thioaldehydes
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The Diels-Alder reaction of thioaldehydes with cyclopentadiene occurs with a preference for the endo isomer.The highest selectivity is observed for thioaldehydes RCHS where R is a bulky group such as tert-butyl or isopropyl.Thioaldehydes having α-alkoxy, acetoxy, or siloxy substituents also react with useful endo selectivity.Secondary orbital overlap is a small factor in these reactions since α-oxo thioaldehydes react with relatively low endo selectivity.Steric effects are primarily responsible for the endo preferences observed.The Diels-Alder reactions of chiral α-oxygen substituted thioaldehydes also occur with useful thioformyl face selectivity.A Cornforth transition state 5 is most likely for the selectivity observed for α-alkoxy or acetoxy thioaldehydes, but the α-hydroxy analogue 23 reacts with the opposite facial preference.The highest face selectivity is obtained with the acetonide of thioglyceraldehyde, generated by photolysis of the phenacyl sulfide 15b.
- Vedejs, E.,Stults, J. S.,Wilde, R. G.
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p. 5452 - 5460
(2007/10/02)
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- DIENOPHILIE DES OLEFINES CAPTODATIVES-VII: CYCLOADDITIONS DE DIELS-ALDER DE L'α-METHYLTHIO-ACRYLATE DE METHYLE, REACTIONS THERMIQUES, REACTIONS CATALYSEES PAR UN ACIDE DE LEWIS ET TRANSFORMATIONS DES ADDUITS
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The Diels-Alder reactions of the α-methylthio methyl acrylate with simple dienes are investigated.The uncatalyzed thermal reactions proceed in high yield.With cyclic dienes they give adducts in wich the carbonyl containing substituent of the major product occupied the exo position.We have shown that with cyclopentadiene the stereoselectivity decreases with increasing temperature.In the presence of a Lewis acid catalyst, the regioselectivity is enhanced and the stereoselectivity is radically reversed.The cycloadducts are amenable to further usefull transformations which illustrate that the α-methylthio methyl acrylate can be used as a synthetic equivalent of either ketene or methoxycarbonyl-acetylene.
- Boucher, Jean-Luc,Stella, Lucien
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p. 3607 - 3616
(2007/10/02)
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- Forbidden Reactions.- Cycloreversion of Rigid Cyclobutanes
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Cyclobutane derivatives, severely restrained from generating noninteractive 1,4-diradicals, are examined thermochemically to provide quantitative evidence to support a forbidden-concerted, antiaromatic mechanism for their cyclorevision.
- Doering, William v. E.,Roth, Wolfgang R.,Breuckmann, Rolf,Figge, Lutz,Lennartz, Hans-Werner,et al.
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- Intramolecular 2H Group-Transfer (Dyotropic Rearrangements) in Alicyclic and Heterocyclic Bridged-Ring Systems
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Examples of alicyclic frameworks containing a cyclohexa-1,3-diene ring as 2H donor held proximate to a variously-substituted acceptor Π-bond are compared for their reactivity in thermal 2H group-transfer reactions.Kinetic analysis reveals marked effects on rearrangement-rate as the acceptor Π-bond substituents are varied.Attempted synthesis of exact structural analogues of these compounds but with a 2,3-diazacyclohexadiene component replacing the cyclohexadiene element usually gives instead products of concomitant 2H group-transfer.These results are compared with the similar but generally slower 2H group-transfer rearrangement of pentacyclic 2-pyrazoline derivatives having relevant critical stereochemical features which result from 1,3 -diarylnitrilimine (4+2)Π adductions with dipolarophiles of the isodrin type.Alkoxy and chlorine substitution of the acceptor Π-bond is rate-retarding for 2H group-transfer in both the alicyclic and heterocyclic representative systems examined, indicating truly pericyclic behaviour.
- Mackenzie, K.,Proctor, G.,Woodnutt, D. J.
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p. 5981 - 5994
(2007/10/02)
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