Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents

Mostrar todas las versiones(2)

The kinetics of the reactions of 2,4-dinitrofluorobenzene (DNFB) and 2,4-dinitrochlorobenzene (DNClB) with 2-guanidinobenzimidazole (2-GB) at 40±0.2°C in dimethylsulphoxide (DMSO), toluene, and in toluene-DMSO mixtures, and with 1-(2-aminoethyl)piperidine (2-AEPip) and N-(3-aminopropyl) morpholine (...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Alvaro, C.E.S., Ayala, A.D., Nudelman, N.S.
Formato: JOUR
Materias:
aprotic solvents
aromatic nucleophilic substitution
dimer nucleophile mechanism
hydrogen bond
hydrogen-bonded nucleophiles
mixed aggregates
Aprotic solvents
Aromatic nucleophilic substitution
Mixed aggregates
Aggregates
Aromatic compounds
Benzene
Catalysis
Dimers
Hydrogen
Nucleophiles
Reaction intermediates
Solvents
Toluene
Hydrogen bonds
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_08943230_v24_n2_p101_Alvaro
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_08943230_v24_n2_p101_Alvaro
record_format dspace
spelling todo:paper_08943230_v24_n2_p101_Alvaro2023-10-03T15:42:04Z Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents Alvaro, C.E.S. Ayala, A.D. Nudelman, N.S. aprotic solvents aromatic nucleophilic substitution dimer nucleophile mechanism hydrogen bond hydrogen-bonded nucleophiles mixed aggregates Aprotic solvents Aromatic nucleophilic substitution dimer nucleophile mechanism hydrogen-bonded nucleophiles Mixed aggregates Aggregates Aromatic compounds Benzene Catalysis Dimers Hydrogen Nucleophiles Reaction intermediates Solvents Toluene Hydrogen bonds The kinetics of the reactions of 2,4-dinitrofluorobenzene (DNFB) and 2,4-dinitrochlorobenzene (DNClB) with 2-guanidinobenzimidazole (2-GB) at 40±0.2°C in dimethylsulphoxide (DMSO), toluene, and in toluene-DMSO mixtures, and with 1-(2-aminoethyl)piperidine (2-AEPip) and N-(3-aminopropyl) morpholine (3-APMo) in toluene at 25±0.2°C were studied under pseudo first-order conditions. For the reactions of 2-GB carried out in pure DMSO, the second-order rate coefficients were independent of the amine concentration. In contrast, the reactions of 2-GB with DNFB in toluene, showed a kinetic behaviour consistent with a base-catalysed decomposition of the zwitterionic intermediate. These results suggest an intramolecular H-bonding of 2-GB in toluene, which is not present in DMSO. To confirm this interpretation the reactions were studied in DMSO-toluene mixtures. Small amounts of DMSO produce significant increase in rate that is not expected on the basis of the classical effect of a dipolar aprotic medium; the effect is consistent with the formation of a nucleophile/co-solvent mixed aggregate. For the reactions of 3-APMo with both substrates in toluene, the second-order rate coefficients, kA, show a linear dependence on the [amine]. 3-APMo is able to form a six-membered ring by an intramolecular H-bond which prevents the formation of self-aggregates. In contrast, a third order was observed in the reactions with 2-AEPip: these results can be interpreted as a H-bonded homo-aggregate of the amine acting as a better nucleophile than the monomer. Most of these results can be well explained within the frame of the 'dimer nucleophile' mechanism. The shown polyamines were selected to examine its ability to form inter- or intra-molecular hydrogen-bonds. The reactions of 2-AEPip with both halodinitro-benzenes in toluene are third order in amine, consistently with the dimer nucleophile mechanism. On the contrary, the intramolecularly hydrogen-bonded structures of 2-GB and 3-APMo prevent formation of dimeric aggregates, the reactions are 2nd.order in amine as expected for the classical base-catalysed ANS. Copyright © 2010 John Wiley & Sons, Ltd. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_08943230_v24_n2_p101_Alvaro
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic aprotic solvents
aromatic nucleophilic substitution
dimer nucleophile mechanism
hydrogen bond
hydrogen-bonded nucleophiles
mixed aggregates
Aprotic solvents
Aromatic nucleophilic substitution
dimer nucleophile mechanism
hydrogen-bonded nucleophiles
Mixed aggregates
Aggregates
Aromatic compounds
Benzene
Catalysis
Dimers
Hydrogen
Nucleophiles
Reaction intermediates
Solvents
Toluene
Hydrogen bonds
spellingShingle aprotic solvents
aromatic nucleophilic substitution
dimer nucleophile mechanism
hydrogen bond
hydrogen-bonded nucleophiles
mixed aggregates
Aprotic solvents
Aromatic nucleophilic substitution
dimer nucleophile mechanism
hydrogen-bonded nucleophiles
Mixed aggregates
Aggregates
Aromatic compounds
Benzene
Catalysis
Dimers
Hydrogen
Nucleophiles
Reaction intermediates
Solvents
Toluene
Hydrogen bonds
Alvaro, C.E.S.
Ayala, A.D.
Nudelman, N.S.
Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents
topic_facet aprotic solvents
aromatic nucleophilic substitution
dimer nucleophile mechanism
hydrogen bond
hydrogen-bonded nucleophiles
mixed aggregates
Aprotic solvents
Aromatic nucleophilic substitution
dimer nucleophile mechanism
hydrogen-bonded nucleophiles
Mixed aggregates
Aggregates
Aromatic compounds
Benzene
Catalysis
Dimers
Hydrogen
Nucleophiles
Reaction intermediates
Solvents
Toluene
Hydrogen bonds
description The kinetics of the reactions of 2,4-dinitrofluorobenzene (DNFB) and 2,4-dinitrochlorobenzene (DNClB) with 2-guanidinobenzimidazole (2-GB) at 40±0.2°C in dimethylsulphoxide (DMSO), toluene, and in toluene-DMSO mixtures, and with 1-(2-aminoethyl)piperidine (2-AEPip) and N-(3-aminopropyl) morpholine (3-APMo) in toluene at 25±0.2°C were studied under pseudo first-order conditions. For the reactions of 2-GB carried out in pure DMSO, the second-order rate coefficients were independent of the amine concentration. In contrast, the reactions of 2-GB with DNFB in toluene, showed a kinetic behaviour consistent with a base-catalysed decomposition of the zwitterionic intermediate. These results suggest an intramolecular H-bonding of 2-GB in toluene, which is not present in DMSO. To confirm this interpretation the reactions were studied in DMSO-toluene mixtures. Small amounts of DMSO produce significant increase in rate that is not expected on the basis of the classical effect of a dipolar aprotic medium; the effect is consistent with the formation of a nucleophile/co-solvent mixed aggregate. For the reactions of 3-APMo with both substrates in toluene, the second-order rate coefficients, kA, show a linear dependence on the [amine]. 3-APMo is able to form a six-membered ring by an intramolecular H-bond which prevents the formation of self-aggregates. In contrast, a third order was observed in the reactions with 2-AEPip: these results can be interpreted as a H-bonded homo-aggregate of the amine acting as a better nucleophile than the monomer. Most of these results can be well explained within the frame of the 'dimer nucleophile' mechanism. The shown polyamines were selected to examine its ability to form inter- or intra-molecular hydrogen-bonds. The reactions of 2-AEPip with both halodinitro-benzenes in toluene are third order in amine, consistently with the dimer nucleophile mechanism. On the contrary, the intramolecularly hydrogen-bonded structures of 2-GB and 3-APMo prevent formation of dimeric aggregates, the reactions are 2nd.order in amine as expected for the classical base-catalysed ANS. Copyright © 2010 John Wiley & Sons, Ltd.
format JOUR
author Alvaro, C.E.S.
Ayala, A.D.
Nudelman, N.S.
author_facet Alvaro, C.E.S.
Ayala, A.D.
Nudelman, N.S.
author_sort Alvaro, C.E.S.
title Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents
title_short Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents
title_full Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents
title_fullStr Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents
title_full_unstemmed Hydrogen-bonded nucleophile effects in ANS: The reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and N-(3-aminopropyl)morpholine in aprotic solvents
title_sort hydrogen-bonded nucleophile effects in ans: the reactions of 1-chloro and 1-fluoro-2,4-dinitrobenzene with 2-guanidinobenzimidazole, 1-(2-aminoethyl) piperidine and n-(3-aminopropyl)morpholine in aprotic solvents
url http://hdl.handle.net/20.500.12110/paper_08943230_v24_n2_p101_Alvaro
work_keys_str_mv AT alvaroces hydrogenbondednucleophileeffectsinansthereactionsof1chloroand1fluoro24dinitrobenzenewith2guanidinobenzimidazole12aminoethylpiperidineandn3aminopropylmorpholineinaproticsolvents
AT ayalaad hydrogenbondednucleophileeffectsinansthereactionsof1chloroand1fluoro24dinitrobenzenewith2guanidinobenzimidazole12aminoethylpiperidineandn3aminopropylmorpholineinaproticsolvents
AT nudelmanns hydrogenbondednucleophileeffectsinansthereactionsof1chloroand1fluoro24dinitrobenzenewith2guanidinobenzimidazole12aminoethylpiperidineandn3aminopropylmorpholineinaproticsolvents
_version_ 1807317419455152128

Ejemplares similares