Agroquímica

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http://repositorio.ufes.br/handle/10/17376
Programa de Pós-Graduação em Agroquímica

Centro: CCENS
Telefone: (28) 3552 8731
URL do programa: http://www.agroquimica.alegre.ufes.br/pos-graduacao/PPGAQ

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Navegando Agroquímica por Assunto "ácidos fenoxiacético"

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    Síntese e avaliação do potencial herbicida de novas N-Fenil-2-Fenoxiacetamidas
    (Universidade Federal do Espírito Santo, 2021-03-10) Corrêa, Kellen Barelo; Pinheiro, Patricia Fontes; https://orcid.org/0000000340195773; http://lattes.cnpq.br/7891884643619330; https://orcid.org/0000000227803167; http://lattes.cnpq.br/2984170022294170; Osório, Vanessa Moreira; https://orcid.org/0000-0001-5156-4568; http://lattes.cnpq.br/3282723304057244; Menini, Luciana Alves Parreira; https://orcid.org/0000-0001-7041-9999; http://lattes.cnpq.br/0824035845605716
    The herbicides belong to the group of pesticides most consumed in Brazil that are used to control weeds, which are unwanted species able to damage crops. Due to the facility to control pests and the possibility to decrease the production costs, the excessive use of herbicides has created an enlargement in the number of weed resistance to commercial herbicides. Therefore, there is a demand to discover substances with potential herbicidal activity. As an alternative, natural compounds and their semi-synthetic derivatives have been widely studied. Regarding these factors, the objective of this aim project was synthesize new molecules that may have herbicidal activity. The natural origin compound thymol was the starting material and it was used to synthesize thymoxyacetic acid by using sodium 2-chloroacetate. This acid was used in the synthesis of four molecules from the N-phenyl-2-phenoxyacetamide class by using aniline and para substituted aniline with Cl, Br, F, DCC [N, N’, dicyclohexylcarbodiimide] and DMAP [4-(dimethylamino) pyridine]. From the thymol, it was obtained the p-chlorothymol by catalytic oxychlorination reaction. This compound was used to synthesize the p-chlorothymoxyacetic acid, which was subjected to reactions in order to produce the matching amides to those obtained from thymoxyacetic acid. Four compounds were obtained of the Nphenyl-2-phenoxyacetamides class containing chlorine in the para position of the thymoxy group. The molecules were synthetized with excellent yields in the last step (90- 99 %) and characterized by mass spectrometry, infrared spectroscopy, hydrogen and carbon nuclear magnetic resonance (1H and 13C NMR) and after subjected to biological assay against lettuce (Lactuca sativa) and sorghum (Sorghum bicolor) to evaluate the potential herbicidal activity. The p-chlorothymol, used as a starting material in the N-phenyl-2-phenoxyacetamined synthesis, was the compound that had the higher herbicidal potential by inhibiting the germination and root growth of lettuce and sorghum. Regarding the N-phenyl-2- phenoxyacetamides class, the molecule N-(4-fluorophenyl)-2- (2-isopropyl-5- methylphenoxy) acetamide showed inhibition to root growth similar to the positive control with selectivity to lettuce seed. The molecules that showed positives results can be tested in greenhouses, and a new herbicide of commercial interest can be obtained.