The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Jaroslav Kvicala - One of the best experts on this subject based on the ideXlab platform.
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methyl fluoroalkanoate as methyl transferring reagent unexpected participation of bal2 SN2 Mechanism in the reaction of methyl 2 3 3 3 tetrafluoro 2 methoxypropanoate with amines
Journal of Fluorine Chemistry, 2016Co-Authors: Bohumil Dolenský, Jaroslav Kvicala, Oldřich PaletaAbstract:Abstract In the reaction of methyl 2,3,3,3-tetrafluoro-2-methoxypropanoate with arylamines or arylmethylamines, an unexpected methyl transfer from the ester to the amine by the BAl2 (SN2) Mechanism was observed leading to the corresponding N-methylamines under specific conditions. The reaction was accompanied by the formation of amides via BAc2 Mechanism. The unexpected methyl transfer is highly dependent on the structure of the starting amine and is supported by the absence of solvent and high temperature.
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
ChemInform, 2011Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Pentafluorobiphenyl (I) reacts completely regioselectively with a variety of O-, S-, and N-nucleophiles furnishing p-substituted derivatives (III).
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
Journal of Fluorine Chemistry, 2010Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Abstract 2,3,4,5,6-Pentafluorobiphenyl (PFBi) was modified by the nucleophilic substitution of one fluorine using a series of O-, S- and N-nucleophiles, viz. alkaline salts of 2,2,2-trifluoro-ethanol, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanol, 1,2;3,4-di-O-isopropylidenexylitol, allylsulfane, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-thiol, 3-aminopropan-1-ol ( 7 ), and tert-butyl N-(3-aminopropyl)carbamate ( 8 ). All the substitutions took place exclusively at the position para to the phenyl group. (3-Amino-propyl)amino derivative of PFBi ( 15 ) was further modified at the terminal amino group by acylation or fluoroalkylation. The reaction of 8 was applied to meso -5,10,15,20-tetrakis-(pentafluorophenyl)porphyrin ( 20 ) to afford tris- ( 21 ) and tetrakis-substituted ( 22 ) products with complete para-regioselectivity. Theoretical studies of the reaction pathways of PFBi with ammonia, microsolvated lithium fluoride or lithium hydroxide revealed that no Meisenheimer-type intermediates are formed in the course of the simulated reactions: instead, tetrahedral S N 2 Mechanism was found. Significant regioselectivity of the nucleophilic aromatic substitution, leading to 4-substituted products, was predicted based on relative transition state energies in agreement with the observed experimental results.
Vladimir Kral - One of the best experts on this subject based on the ideXlab platform.
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
ChemInform, 2011Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Pentafluorobiphenyl (I) reacts completely regioselectively with a variety of O-, S-, and N-nucleophiles furnishing p-substituted derivatives (III).
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
Journal of Fluorine Chemistry, 2010Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Abstract 2,3,4,5,6-Pentafluorobiphenyl (PFBi) was modified by the nucleophilic substitution of one fluorine using a series of O-, S- and N-nucleophiles, viz. alkaline salts of 2,2,2-trifluoro-ethanol, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanol, 1,2;3,4-di-O-isopropylidenexylitol, allylsulfane, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-thiol, 3-aminopropan-1-ol ( 7 ), and tert-butyl N-(3-aminopropyl)carbamate ( 8 ). All the substitutions took place exclusively at the position para to the phenyl group. (3-Amino-propyl)amino derivative of PFBi ( 15 ) was further modified at the terminal amino group by acylation or fluoroalkylation. The reaction of 8 was applied to meso -5,10,15,20-tetrakis-(pentafluorophenyl)porphyrin ( 20 ) to afford tris- ( 21 ) and tetrakis-substituted ( 22 ) products with complete para-regioselectivity. Theoretical studies of the reaction pathways of PFBi with ammonia, microsolvated lithium fluoride or lithium hydroxide revealed that no Meisenheimer-type intermediates are formed in the course of the simulated reactions: instead, tetrahedral S N 2 Mechanism was found. Significant regioselectivity of the nucleophilic aromatic substitution, leading to 4-substituted products, was predicted based on relative transition state energies in agreement with the observed experimental results.
Daniel Derouet - One of the best experts on this subject based on the ideXlab platform.
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synthesis of n n diethyldithiocarbamate functionalized 1 4 polyisoprene from natural rubber and synthetic 1 4 polyisoprene
European Polymer Journal, 2007Co-Authors: Daniel Derouet, Quang Ngoc Tran, Ha H ThucAbstract:Abstract N,N-Diethyldithiocarbamate functionnalized 1,4-polyisoprenes were prepared from 1,4-polyisoprenes (natural or synthetic). The syntheses were performed by nucleophilic addition of N,N-diethyldithiocarbamate salts upon oxirane rings of epoxidized units according to a SN2 Mechanism with ring opening. Studies on model molecules of epoxidized 1,4-polyisoprene units (1,2-epoxy-1-methylcyclohexane and 4,5-epoxy-4-methyloctane) were previously achieved to develop the procedure. The best yields were obtained at low temperature in polar medium, and more especially in water with sodium N,N-diethyldithiocarbamate (DEDT-Na) as reagent. A diastereospecific addition was noted when reaction was performed in water with DEDT-Na. Afterwards, the developed procedure was successfully generalized to epoxidized synthetic polyisoprenes and epoxidized natural rubber (in THF, then in latex medium). Excellent results were obtained in latex medium with epoxidized natural rubber (ENR) latices. As with the models, a diastereospecific addition of sodium N,N-diethyldithiocarbamate trihydrate onto epoxidized 1,4-polyisoprene units of ENR was observed at the condition to bring the latex medium to pH 8 before introduction of DEDT-Na. Influence of temperature, drc, and DEDT-Na concentration were successively examined to determine the best conditions of the addition on ENR latices.
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alcoholysis of epoxidized polyisoprenes by direct opening of oxirane rings with alcohol derivatives 1 modelization of the reaction
European Polymer Journal, 2001Co-Authors: Daniel Derouet, Jeanclaude Brosse, Allal ChalliouiAbstract:Abstract Alcoholysis of 4,5-epoxy-4-methyloctane selected as a model molecule of epoxidized 1,4-polyisoprene was achieved with various alcohols using cerium ammonium nitrate as catalyst. Next to the expected alkoxy alcohol, side products resulting from oxirane rearrangement were identified: 5-methyloctan-4-one, 5-methyloct-5-en-4-ol and 2-n-propylhexen-3-ol. One of them, 5-methyloct-3-en-4-ol, was demonstrated to be able to react with alcohols so leading to the formation of allylic ethers. From the diastereoisomer distribution, as well as the effect of temperature and solvent on the reaction, a coordinative SN2 Mechanism able to explain the formation of the various products identified, is suggested.
Oldrich Paleta - One of the best experts on this subject based on the ideXlab platform.
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
ChemInform, 2011Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Pentafluorobiphenyl (I) reacts completely regioselectively with a variety of O-, S-, and N-nucleophiles furnishing p-substituted derivatives (III).
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
Journal of Fluorine Chemistry, 2010Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Abstract 2,3,4,5,6-Pentafluorobiphenyl (PFBi) was modified by the nucleophilic substitution of one fluorine using a series of O-, S- and N-nucleophiles, viz. alkaline salts of 2,2,2-trifluoro-ethanol, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanol, 1,2;3,4-di-O-isopropylidenexylitol, allylsulfane, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-thiol, 3-aminopropan-1-ol ( 7 ), and tert-butyl N-(3-aminopropyl)carbamate ( 8 ). All the substitutions took place exclusively at the position para to the phenyl group. (3-Amino-propyl)amino derivative of PFBi ( 15 ) was further modified at the terminal amino group by acylation or fluoroalkylation. The reaction of 8 was applied to meso -5,10,15,20-tetrakis-(pentafluorophenyl)porphyrin ( 20 ) to afford tris- ( 21 ) and tetrakis-substituted ( 22 ) products with complete para-regioselectivity. Theoretical studies of the reaction pathways of PFBi with ammonia, microsolvated lithium fluoride or lithium hydroxide revealed that no Meisenheimer-type intermediates are formed in the course of the simulated reactions: instead, tetrahedral S N 2 Mechanism was found. Significant regioselectivity of the nucleophilic aromatic substitution, leading to 4-substituted products, was predicted based on relative transition state energies in agreement with the observed experimental results.
Michal Benes - One of the best experts on this subject based on the ideXlab platform.
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
ChemInform, 2011Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Pentafluorobiphenyl (I) reacts completely regioselectively with a variety of O-, S-, and N-nucleophiles furnishing p-substituted derivatives (III).
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regiospecific nucleophilic substitution in 2 3 4 5 6 pentafluorobiphenyl as model compound for supramolecular systems theoretical study of transition states and energy profiles evidence for tetrahedral SN2 Mechanism
Journal of Fluorine Chemistry, 2010Co-Authors: Jaroslav Kvicala, Michal Benes, Oldrich Paleta, Vladimir KralAbstract:Abstract 2,3,4,5,6-Pentafluorobiphenyl (PFBi) was modified by the nucleophilic substitution of one fluorine using a series of O-, S- and N-nucleophiles, viz. alkaline salts of 2,2,2-trifluoro-ethanol, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctanol, 1,2;3,4-di-O-isopropylidenexylitol, allylsulfane, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctane-1-thiol, 3-aminopropan-1-ol ( 7 ), and tert-butyl N-(3-aminopropyl)carbamate ( 8 ). All the substitutions took place exclusively at the position para to the phenyl group. (3-Amino-propyl)amino derivative of PFBi ( 15 ) was further modified at the terminal amino group by acylation or fluoroalkylation. The reaction of 8 was applied to meso -5,10,15,20-tetrakis-(pentafluorophenyl)porphyrin ( 20 ) to afford tris- ( 21 ) and tetrakis-substituted ( 22 ) products with complete para-regioselectivity. Theoretical studies of the reaction pathways of PFBi with ammonia, microsolvated lithium fluoride or lithium hydroxide revealed that no Meisenheimer-type intermediates are formed in the course of the simulated reactions: instead, tetrahedral S N 2 Mechanism was found. Significant regioselectivity of the nucleophilic aromatic substitution, leading to 4-substituted products, was predicted based on relative transition state energies in agreement with the observed experimental results.
