Tesis
Síntese de chalconas substituídas e seus híbridos na busca de novos herbicidas
Fecha
2020-03-31Registro en:
PÁDUA, Geilly Mara Silva de. Síntese de chalconas substituídas e seus híbridos na busca de novos herbicidas. 2020. 105 f. Dissertação (Mestrado em Química) - Universidade Federal de Mato Grosso, Instituto de Ciências Exatas e da Terra, Cuiabá, 2020.
Autor
Vieira, Lucas Campos Curcino
http://lattes.cnpq.br/1662838473695956
Vieira, Lucas Campos Curcino
081.860.436-08
http://lattes.cnpq.br/1662838473695956
Campos, Marcelo Lattarulo
004.748.721-65
http://lattes.cnpq.br/5284850915993707
081.860.436-08
Bernardes, Aline
025.682.531-93
http://lattes.cnpq.br/8754978879262396
Institución
Resumen
For several years, the commonly marketed synthetic herbicides have been the
main method of weed management. However, the emergence of herbicide resistance
and its negative effects on both health and the environment induced an increased
social concern about its use and stimulated the interest in discovering ecological
herbicidal compounds without compromising the production of agricultural culture.
Considering this need, the present study synthesized a collection of chalcone
derivatives and evaluated their ability to inhibit photosynthesis by blocking electron
transport. In the first part of this study, Claisen Schmidt condensation was used to
synthesize chalcones with different substituents, grouped in either electron donor or
receptor donor (55a-m), and the yields ranging between 27-98%. The herbicidal
activity of chalcones was determined by three tests. In a preliminary test,
measurements of a chlorophylls fluorescence in spinach discs were made after
exposing the compounds 55a-m to 100μM, in order to make a pre-selection of more
active compounds. The substances 55a, 55d, 55g, 55i, 55j, 55k and 55l were the most
active compounds in the semi in vivo test and therefore were forwarded to the in vivo
test performed on the species Ipomoea grandifolia. Chalcones 55a, 55d, 55g and 55k l have been shown to inhibit electron flow in FSII and FSI causing a decrease in the
biomass production of the weed I. grandfolia. Among those, the compounds 55a and
55g are selective for maize cultivation while compounds 55a and 55l are selective for
bean cultivation. The elucidation of the mechanism of action of these compounds may
be considered a relevant contribution in this area, since there are no reports in the
literature about the use of these chalcones as photosynthesis inhibitors. In the second
part of this study, chalcones 55e and 55j were reduced for their subsequent use in the
multicomponent reaction to form chalcone hydrotriazine 57, which was obtained with
90% yield. A reaction methodology was developed using the nucleophilic aromatic
substitution reaction with chalcone 55k and indole 62 producing the hybrid chalcone indole 63 with 58% yield, a compound not yet reported in the literature. In order to
conclude the present study, the next step will focus on elucidating the herbicidal activity
of the formed molecular hybrid compounds.