- RADICAL CATIONS OF VARIOUS ETHENE, ETHINE AND CYCLIC ETHERS
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We have prepared the cations .(1+), .(1+) and .(1+) by the action of ionizing radiation on dilute solutions of neutral precursors in freon at 77 K, and used e.s.r. spectroscopy to study their structures.We have also studied the cations of oxirane, oxetane and methoxyethine for comparative purposes.
- Symons, Martyn C. R.,Wren, Brendon W.
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- Photochemical reactions of trimethylene oxide radical cations in Freon matrices at 77 K
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Radical cations of trimethylene oxide under photobleaching at 77 K could form either distonic radical cations ·CH2CH2CH=OH+/·CH2CH2O+=CH2 or oxetan-2-yl radicals depending on the Freon matrix used.
- Mel'nikov, Mikhail Ya.,Belevskii, Vladilen N.,Kalugina, Anastasiya D.,Mel'nikova, Ol'ga L.,Pergushov, Vladimir I.,Tyurin, Daniil A.
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- Study of the low temperature oxidation of propane
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The low-temperature oxidation of propane was investigated using a jet-stirred reactor at atmospheric pressure and two methods of analysis: gas chromatography and synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) with direct sampling through a molecular jet. The second method allowed the identification of products, such as molecules with hydroperoxy functions, which are not stable enough to be detected by gas chromatography. Mole fractions of the reactants and reaction products were measured as a function of the temperature (530-730 K), with a particular attention to reaction products involved in the low temperature oxidation, such as cyclic ethers, aldehydes, alcohols, ketones, and hydroperoxides. A new model has been obtained from an automatically generated one, which was used as a starting point, with a large number of re-estimated thermochemical and kinetic data. The kinetic data of the most sensitive reactions, i.e., isomerizations of alkylperoxy radicals and the subsequent decompositions, have been calculated at the CBS-QB3 level of theory. The model allows a satisfactory prediction of the experimental data. A flow rate analysis has allowed highlighting the important reaction channels.
- Cord, Maximilien,Husson, Benoit,Lizardo Huerta, Juan Carlos,Herbinet, Olivier,Glaude, Pierre-Alexandre,Fournet, Rene,Sirjean, Baptiste,Battin-Leclerc, Frederique,Ruiz-Lopez, Manuel,Wang, Zhandong,Xie, Mingfeng,Cheng, Zhanjun,Qi, Fei
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p. 12214 - 12228
(2013/02/25)
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- Coating composition comprising a bicyclo- or spiro-orthoester functional compound
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The invention pertains to a coating composition comprising a first compound comprising at least one bicyclo- or spiro-orthoester group and a second compound comprising at least two hydroxyl-reactive groups. The invention also comprises a process for curing the present coating composition. More particularly, the latent hydroxyl groups of the bicyclo- or spiro-orthoester groups have to be deblocked and reacted with the hydroxyl-reactive groups of the second compound if the present coating composition is to be cured. Further, a process for making bicyclo-orthoester compounds from the corresponding oxetane compound is described, as are polymers comprising at least one bicyclo- or spiro-orthoester group.
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- Spiro-cyclic beta-amino acid derivatives as inhibitors of matrix metalloproteases and TNF-alpha converting enzyme (TACE)
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The present application describes novel spiro-cyclic β-amino acid derivatives of formula I: or pharmaceutically acceptable salt forms thereof, wherein ring B is a 3-13 membered carbocycle or heterocycle, ring C forms a 3-11 membered spiro-carbocycle or spiro-heterocycleon ring B, and the other variables are defined in the present specification, which are useful as as matrix metalloproteinases (MMP), TNF-α converting enzyme (TACE), and/or aggrecanase inhibitors.
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- Method for the preparation of 1-deoxy baccatin III, 1-deoxy taxol and 1-deoxy taxol analogs
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1-Deoxybaccatin III, 1-deoxytaxol and 1-deoxy taxol analogs and method for the preparation thereof.
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- Process for production of an oxetane
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A process for production of an oxetane, which process comprises subjecting an alcohol having two or more hydroxyl groups to reaction with a carbamide at a molar ratio employing 1-2 moles of said carbamide on 1-2 moles of said alcohol. The alcohols preferably have at least one 1,3-diol grouping. The reaction is carried out in the presence of at least one catalyst promoting and/or initiating transcarbonylation and/or pyrolysis. A reaction mixture comprising an oxetane and optionally an orthocarbonate of said alcohol is yielded. The oxetane is suitable recovered from said reaction mixture by for instance distillation.
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- Tricyclic and tetracyclic taxanes
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The synthesis of taxol and other tricyclic and tetracyclic taxanes.
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- Hydrogen bonding Part 44 1Thermodynamics of complexation of 3,5-dichlorophenol with ketones and ethers in cyclohexane: The badger-Bauer relationship
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Equilibrium constants for 1 : 1 hydrogen bond complexation between 3,5-dichioropheno' (DCP) and 17 ketones and 12 ethers in cyclohexane solution have been obtained by an FTIR method that takes into account both diiaerization of the acid and formation of 2 :1 complexes. Enthalpies of complexation for the same ketones and ethers have been determined by a calorimeiric method, leading to values of log K, AG, AH and AS0 for 1 :1 complexation in the 29 systems, as well as log K2 for the 2 :1 complexation between 2 mol of acid and 1 mol of base. For the ketone systems there is very little variation in the three thermodynamic parameters with alkyl substitution, but for the ethers there are systematic variations depending on the alkyl substituent or if the ethers are cyclic. Values of the OH stretching frequency in the DCP complexes with the ketones and ethers in cyclohexane have been obtained. The band shapes for the DCP-ketone complexes are very asymmetric, possibly due to the presence of stereoisomeric complexes, but the VOH band for DCP-ether complexes is symmetric and very suitable for the evaluation of any relationship between v()H and A/f. It is found that for the complexation of DCP with the 12 aliphatic ethers in cyclohexane, there is almost no connection between the calorimetrically determined AH° values and values of AvOH.
- Abraham, Michael H.,Prior, David V.,Schulz, Ronald A.,Morris, Jeffrey J.,Taylor, Peter J.
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p. 879 - 885
(2007/10/03)
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- Total synthesis of taxol and analogues thereof
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The present invention provides three basic routes for the total synthesis of taxol having the structure: STR1 The present invention also provides the intermediates produced in the above processes, processes for synthesizing these intermediates as well as analogues of taxol and nortaxol.
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- Synthetic process for the preparation of tricyclic and tetracyclic taxanes
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Process for the synthesis of taxol and other tricyclic and tetracyclic taxanes.
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- Tricyclic and tetracyclic taxanes
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The synthesis of taxol and other tricyclic and tetracyclic taxanes.
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- Total synthesis of taxol and analogues thereof
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The present invention provides three basic routes for the total synthesis of taxol having the structure: STR1 The present invention also provides the intermediates produced in the above processes, processes for synthesizing these intermediates as well as analogues of taxol and nortaxol.
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- Process for preparing polyfluorooxetanes
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This invention concerns a process for the preparation of polyfluorooxetanes by the reaction of fluoroketones or fluoroepoxides with haloethylenes in the presence of a Lewis acid catalyst. Polyfluorooxetanes are useful as solvents and plasticizers having high thermal stability.
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- Synthetic process for the preparation of taxol and other tricyclic and tetracyclic taxanes
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Process for the synthesis of taxol and other tricyclic and tetracyclic taxanes.
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- Total synthesis of taxol
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The present invention provides two basic routes for the total synthesis of taxol having the structure: STR1 The present invention also provides the intermediates produced in the above processes, processes for synthesizing these intermediates as well as analogs to taxol. Both the intermediates and analogs to taxol may prove to be valuable anticancer agents.
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- Process for the production of polyethers derived from oxetanes
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Hydroxyterminated prepolymers, used in curing reactions with isocyanates to produce elastomers, are prepared by continuously adding over periods of 12-50 hours an oxetane monomer to a reaction mixture containing a diol initiator and a catalyst capable of catalyzing the cationic quasi-living cationic polymerization of the monomer, the rate of addition to maintain stoichiometric excess over the monomer. Polymerization is terminated by adding brine. Polymers of increased molecular weight and reduced impurity levels result.
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- Processes for the preparation of cyclic ethers
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A process for preparing cyclic ethers which comprises contacting a carboxylated ether with a mixed metal oxide catalyst under conditions effective to produce the cyclic ether.
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- Decarboxylation processes using mixed metal oxide catalysts
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A decarboxylation process which comprises contacting a carboxylated compound with a metal oxide catalyst under conditions effective to decarboxylate the carboxylated compound.
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- N, N-disubstituted oligourethanes and polyurethanes, a process for their preparation, and their use in the production of plastics
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The present invention relates to N,N-disubstituted compounds containing urethane groups and terminal hydroxyl groups corresponding to the general formula STR1 wherein X is the residue of a strong memobasic or polybasic acid remaining after dissociation of the proton or protons of said acid or a hydroxyl group; Y is an n-functional hydrocarbon group having a molecular weight of from about 15 to about 8000 (preferably from about 300 to about 4000) and optionally interrupted by oxygen, sulfur, or silicon atoms, or by ester, carbonate, urea, N-monosubstituted urethane, or N,N-disubstituted urethane groups; 1R hydrogen or a hydrocarbon group having a molecular weight of from about 15 to about 200; 2R is the radical of an alkylating or arylating agent; and is an integer of from 2 to about 6. The present invention further relates to a process for preparing such compounds and to a method for using such compounds in the production of plastics.
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- Cyclic Trimerization of Oxetanes
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Conditions for obtaining the optimum yield of the cyclic trimer in the cationic oligomerization of oxetanes have been determined.At moderate dilution (0.05 M) with catalytic quantities of BF3 in CH2Cl2, the yield of the cyclic trimer (1,5,9-trioxacyclododecane) from oxetane could be increased to 50percent at the expense of the cyclic tetramer (1,5,9,13-tetraoxacyclohexadecane), 12percent, and polymer.In contrast, 3,3-dimethyloxetane consumed the BF3 catalyst, which had to be renewed, producing, in a slow reaction, a homologous series of fluorohydrins, together with cyclic oligoethers.The fluorohydrins cyclized if treated with gaseous BF3 before work-up, boosting the isolated yields to 20percent cyclic trimer and 8percent cyclic tetramer.With PF5 in CH2Cl2 the catalyst was stable and the reaction fast, and no fluorohydrins were formed; no cyclic trimer but 73percent cyclic tetramer could be isolated.Other solvents (benzene, CHCl=CCl2, CH2ClCH2Cl), other catalysts (SbF5, AlEt3) and other oxetanes (3-methoxymethyl-3-methyloxetane, 3-halomethyl-3-methyloxetane) were also examined.
- Dale, Johannes,Fredriksen, Siw B.
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- The Synthesis of Oxiranes and Oxetanes from 1,2- or 1,3-Halohydrins Using Organoantimony(V) Alkoxide
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Tetraphenylstibonium methoxide (1) is an effictive reagent for the synthesis of oxiranes and oxetanes from the corresponding 1,2- and 1,3-halohydrins, respectively.As the reaction conditions are neutral, oxiranes bearing an ester moiety were obtained intact without undergoing solvolysis.In addition, oxetanes, whose preparation was not generally facile, were formed in good yields under mild conditions (60-80 deg C).
- Fujiwara, Masahiro,Hitomi, Kazuhisa,Baba, Akio,Matsuda, Haruo
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p. 106 - 109
(2007/10/02)
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- Perkin-Markovnikov Type Reaction Initiated with Electrogenerated Superoxide Ion
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The cyclic condensation of α,ω-dihaloalkanes with acticvated methylene of malonic acid and acetoacetic acid esters is studied using an electrogenerated superoxide ion.Two possible mechanisms for this reaction are postulated.
- Ojima, Fumihiro,Matsue, Tomokazu,Osa, Tetsuo
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p. 2235 - 2238
(2007/10/02)
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- THE SYNTHETIC UTILITY OF DIOXYPHOSPHORANES IN ORGANIC SYNTHESIS
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Diethoxytriphenylphosphorane, DTPP, prepared by reaction of triphenylphosphine and diethyl peroxide, is a "hydrolytically active" dioxyphosphorane which promotes mild and efficient cyclodehydration of diols to cyclic ethers in neutral media.Simple 1,2-, 1,4-, and 1,5-diols afford good yields of the cyclic ethers but 1,3-propanediol and 1,6-hexanediol give mainly 3-ethoxy-1-propanol and 6-ethoxy-1-hexanol, respectively, with DTPP.Tri- and tetra-substituted 1,2-diols afford the relatively stable 1,3,2-dioxaphospholanes in the presence of DTPP and the reaction conditions dictate whether epoxides, ketones, or allylic alcohols are obtained.
- Robinson, Philip L.,Kelly, Jeffery W.,Evans, Slayton A.
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- Vacuum-ultraviolet photlysis (185) nm of liquid 1,3-dioxan
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1,3-Dioxan photolytic destruction at 185 nm occurs with a quantum yield of about 0.3 in the liquid phase.Of the 22 products determined, the major ones are n-propylformate (φ = 0.10), formaldehyde (0.075), 1,3-diox-4-en (0.06), hydrogen (0.05), ethylene (0.04), and 3-methoxypropionaldehyde (0.04).A number of the minor products are of the general type B, some of which bear a hydroxyl function at the end of the side chain.N2O interacts with excited 1,3-dioxan, leading to the production of N2.Some experiments have been carried out in the vapour phase, the results of which indicate that considerable fragmentation of hot primary intermediates and products into low-molecular-weight products occurs.The nature of these products cannot be linked directly to the primary photolytic process inferred from the liquid-phase studies.Certain contrasts in the photolytic behaviour of 1,3-dioxan and 1,4-dioxan are discussed.
- Schuchmann, Heinz-Peter,Clemens, Sonntag von
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p. 1833 - 1839
(2007/10/02)
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- Diethoxytriphenylphosphorane: A Mild, Regioselective Cyclodehydrating Reagent for Conversion of Diols to Cyclic Ethers. Stereochemistry, Synthetic Utility, and Scope
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Diethoxytriphenylphosphorane, Ph3P(OEt)2, prepared by reaction of triphenylphosphine and diethyl peroxide, is a "hydrolytically active" dioxyphosphorane which promotes mild cyclodehydration (40-110 deg C) of diols to cyclic ethers in neutral media.The regioselectivity in the closure of (S)-(+)-propane-1,2-diol and (R)-(-)-pentane-1,4-diol with Ph3P(OEt)2 is high (81-82 percent) while the cyclodehydration of (S)-(+)-phenylethane-1,2-diol gives racemized (+/-)-styrene oxide.Simple 1,2-, 1,4-, and 1,5-diols afford good yields of the cyclic ethers but 1,3-propanediol and 1,6-hexanediol give mainly 3-ethoxy-1-propanol and 6-ethoxy-1-hexanol, respectively with Ph3P(OEt)2.Tri- and tetra-substituted 1,2-diols afford the relatively stable 1,3,2-dioxaphospholanes (or ?-dioxyphosphoranes) in the presence of Ph3P(OEt)2, and, depending on conditions, the 1,3,2-dioxaphospholanes are selectively converted to epoxides, ketones or allylic alcohols.The carbonyl compounds arise from 1,2-hydride and 1,2-methyl migrations; the allylic alcohols are derived from thermolytic eliminations. trans-1,2-Cyclohexanediols afford essentially quantitative yields (>95 percent) of the cyclohexene oxides while cis-1,2-cyclohexanediol gives the stable 1,3,2-dioxaphospholane with Ph3P(OEt)2 which decomposes under thermal conditions to cyclohexanone (90 percent).Ph3P(OEt)2 is extremely useful for conversion of "sensitive" 1,2-diols to acidic and /or thermally labile epoxides as demonstrated by the quantitative conversion of 9,10-dihydro-trans-9,10-phenanthrenediol to 9,10-dihydrophenanthrene oxide and 2α,10-pinanediol to 2α,10-epoxypinane.
- Robinson, Philip L.,Barry, Carey N.,Kelly, Jeffery W.,Evans, Slayton A.
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p. 5210 - 5219
(2007/10/02)
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- REACTION D'ADDITION EN SOLUTION D'H2S SUR LE PROPYLENE PHOTOINITIEE PAR LE BENZOPHENONE EN PRESENCE DE PHOSPHITES ALIPHATIQUES. II - ETUDE DES INTERACTIONS ENTRE REACTIFS
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Aliphatic phosphites quench strongly the triplet of benzophenone (Kq ca. 1-3 * 108 l.mole-1 sec-1), but do not interact with isobentopinacol or with the instable adduct formed by reaction of Ph2COH with Ph. when the photoreaction is performed in benzene.They do not interact either with ketyl radicals.It has been proved that benzophenone photoexcited is quenched by H2S (Kq = 2.65 * 106 l.mole-1 sec-1) but do not abstract an hydrogen of this compound.The formation of HS which is the initiation step of the benzophenone photoinitiated addition in solution of H2S to propylene is Ph2CO.3 + solvent with labil H (SvH) --> Ph2C.OH + Sv. or (and) + CH3-CH=CH2 --> Ph2C.OH + .CH2-CH=CH2 H2S + Sv. or (and) CH-CH=CH2 --> SvH or (and) CH3-CH=CH2 + HS.
- Brehon, Annick,Couture, Axel,Combier, Lablache
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p. 851 - 860
(2007/10/02)
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- A New Four-centre Reaction of Alkanol-Alkoxide Negative Ions. The Reaction of with Alkoxysilanes. An Ion Cyclotron Resonance Study
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Alkanol-alkoxide negative ions 1O...H...OR2>(-) react with alkoxysilanes Me3SiOR3 to produce both 1O(-)> and 2O(-)> ions of trigonal bipyramidal geometry.When R1 2 and either R1 or R2 >= Pr, the four-center reaction 1O...H...OR2>(-) + Me3SiOR3 -> 2O...H...OR3>(-) + Me3SiOR1 is observed.Addition of 1O...H...OR2>(-) in the reverse direction is not detected.Analogous reactions do not occur between Me3SiX and 1O...H...OR2>(-) when X = F, NHR, NR2, SiMe3, alkyl, allyl, propargyl, benzyl, or aryl, but 1O...H...X>(-) ions of small abundance are formed when X = HO, OCOMe, OCN, and SR.Cyclic ethers react with alkanol-alkoxyde negative ions by reaction (i;n = 2-4).
- Hayes, Roger N.,Bowie, John H.,Klass, Gunter
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p. 1167 - 1174
(2007/10/02)
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- Gaseous 1-Methyl-1-oxoniacycloalkanes as Stable Intermediates on the C3H7O+ and C4H9O+ Potential Energy Surfaces
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The nature and the isomeric distribution of the neutral products obtained from the gas-phase attack of CH5+, C2H5+, and CH3FCH3+ ions on cyclic CnH2nO (n = 2, 3, and 4) ethers provide the first experimental evidence in favour of 1-methyl-1-oxoniacyclopropane and 1-methyl-1-oxoniacyclobutane as stable intermediates on the corresponding potential energy surface.
- Angelini, Giancarlo,Speranza, Maurizio
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p. 1217 - 1219
(2007/10/02)
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- Polar Substituent Effects in the Solvolysis of Primary and Tertiary Alkyl Halides. Polar Effect IX
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When the Hammett-Taft equation log (k/k0) = ρq ?qi is applied to the solvolysis of the 3-substituted propyl bromides 6a-6i in ethanol/water 4:1 (v/v) log k correlates linearly with ?qI except in cases where R exerts an anchimetric effect.The reaction constant ρq for 6 is -0.12 and is typical for a nucleophilic solvent assisted ks process at a primary C-atom.The tertiary halides 1 and 3, however, which reacty with little or no nucleophilic solvent assistance, i.e. by kc processes, lead to larger ρq values of -0.71 and -1.14, respectively.The reacton constant ρq is therefore a sensitive gauge for charge development in the transition state for solvolysis of satured compounds.
- Grob, Cyril A.,Waldner, Adrian
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p. 2152 - 2158
(2007/10/02)
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