A Regioquímica das Relações de DIELS-ALDER de N-TOSIL PARA-BENZOQUINONA IMINAS
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Data
2012-02
Autores
Uliana, Marciana Pierina
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Neste trabalho foi realizado um estudo comparativo da reatividade de
diferentes dienófilos: para-benzoquinonas, suas mono-oximas, suas mono-oximas
tosiladas e as suas N-tosiliminas frente às reações de Diels-Alder com dienos
simples. A síntese destes dienófilos foi realizada através de algumas modificações
químicas a partir dos fenóis correspondentes como representado no Esquema I.
Foi realizado o estudo de reatividade dos diferentes dienófilos frente às
reações de Diels-Alder com o ciclopentadieno, sendo obtidos os respectivos
cicloadutos (Esquema II).
A reatividade dos dienófilos N-tosiliminas de para-benzoquinonas foram
testada frente às reações de Diels-Alder com os dienos 2,3-dimetil-1,3-butadieno e
com o 2-metil-1,3-butadieno (isopreno) (Esquema III).
Concomitantemente ao estudo experimental sobre a reatividade destes
dienófilos, foi realizado um estudo de cálculos teóricos onde foram obtidas as
diferenças de energia entre os orbitais HOMO do ciclopentadieno e LUMO dos
diferentes dienófilos, podendo assim, confirmar sua reatividade. Os cálculos foram
realizados usando-se a base de cálculo DFT B3LYP/6-31+G(d,p), podendo ser
obtidos os valores de energias dos estados de transição dos diferentes cicloadutos,
podendo-se prever qual produto de cicloadição seria formado de forma majoritária
e determinar quais seriam os produtos cinéticos e os termodinâmicos.
Foram realizados em colaboração com o Professor Dr: Damião Pergentino de
Sousa da UFSE, testes de atividade biológica das para-benzoquinonas, mono-
oximas e mono-oximas tosiladas, os quais apresentam atividade biológica.
In this work it was done a comparative study on the reactivity of a variety of dienophiles including para-benzoquinones, their mono-oximes, their N-tosyl mono-oximes and their N-tosylimines on the Diels-Alder reactions with simple dienes. The synthesis of the dienophiles was performed through chemical modifications from the corresponding phenols as represented in Scheme I. The studies of the reactivity of these dienophiles in the Diels-Alder reactions with cyclopentadiene were the first to be conducted and furnished the corresponding cycloadducts as shown in the Scheme II.The reactivity of the N-tosylimines para-benzoquinones were tested on the Diels-Alder reactions with of the dienes 2,3-dimethyl-1,3-butadiene and 2-methyl- 1,3-butadiene (isoprene) (Scheme III).Concomitant to the experimental study on the reactivity of the dienophiles, it was done a study of theoretical calculations where was obtained the differences between the energies of the HOMO orbital of the cyclopentadiene and LUMO orbitals of the dienophiles confirming their reactivity. These calculations were performed using the DFT calculation using the basis set B3LYP/6-31 + G (d,p) and furnished the energies of the transition states of the cycloadducts. It was also possible to predict which cycloaddition product would be mainly formed and to determine what are the kinetic and thermodynamic products. Tests of the biological activity of the dienophiles were conducted in collaboration with Professor Dr: Damião P. de Sousa from UFSE.
In this work it was done a comparative study on the reactivity of a variety of dienophiles including para-benzoquinones, their mono-oximes, their N-tosyl mono-oximes and their N-tosylimines on the Diels-Alder reactions with simple dienes. The synthesis of the dienophiles was performed through chemical modifications from the corresponding phenols as represented in Scheme I. The studies of the reactivity of these dienophiles in the Diels-Alder reactions with cyclopentadiene were the first to be conducted and furnished the corresponding cycloadducts as shown in the Scheme II.The reactivity of the N-tosylimines para-benzoquinones were tested on the Diels-Alder reactions with of the dienes 2,3-dimethyl-1,3-butadiene and 2-methyl- 1,3-butadiene (isoprene) (Scheme III).Concomitant to the experimental study on the reactivity of the dienophiles, it was done a study of theoretical calculations where was obtained the differences between the energies of the HOMO orbital of the cyclopentadiene and LUMO orbitals of the dienophiles confirming their reactivity. These calculations were performed using the DFT calculation using the basis set B3LYP/6-31 + G (d,p) and furnished the energies of the transition states of the cycloadducts. It was also possible to predict which cycloaddition product would be mainly formed and to determine what are the kinetic and thermodynamic products. Tests of the biological activity of the dienophiles were conducted in collaboration with Professor Dr: Damião P. de Sousa from UFSE.
Abstract
Descrição
Tese apresentada à Universidade
Federal de São Carlos, como parte das
exigências para a obtenção do título de
DOUTOR EM CIÊNCIAS na área de
concentração: QUÍMICA ORGÂNICA.
Orientador:Prof. Dr. Timothy John Brocksom
Palavras-chave
Regioquímica, Diels-Alder, Para-Benzoquinonas