Título:	Síntese de α-aciloxiamidas e heterociclos via reações multicomponentes mediadas por micro-ondas e avaliação de suas atividades fitotóxicas
Autor(es):	Martinho, Luan Alves
Orientador(es):	Andrade, Carlos Kleber Zago de
Assunto:	Reações multicomponentes (Química) Fitotoxicidade Diastereosseletividade Fluorescência
Data de publicação:	24-Nov-2025
Data de defesa:	28-Mar-2025
Referência:	MARTINHO, Luan Alves. Síntese de α-aciloxiamidas e heterociclos via reações multicomponentes mediadas por micro-ondas e avaliação de suas atividades fitotóxicas. 2025. 1111 f., il. Tese (Doutorado em Química) — Universidade de Brasília, Brasília, 2025.
Abstract:	Multicomponent reactions have attracted great interest due to their synthetic efficiency, high atomic economy and ability to generate structural diversity in organic molecules. In Chapter I, Cyrene, a prochiral ketone derived from cellulose residues, was used in the synthesis of novel α-acyloxyamide derivatives via the three-component Passerini reaction (P-3CR) under solvent-free conditions and microwave heating, resulting in high yields and diastereoselectivity. Computational studies suggest that diastereoselectivity is influenced by both kinetics and thermodynamics, with a predominance of thermodynamics. In Chapter II, a simple Passerini reaction approach was employed for the synthesis of α-hydroxyamides, using oxalic acid with various aldehydes/ketones and isocyanides. The new methodology enabled the formation of the α-hydroxyamide group through an intramolecular mechanism of decarboxylation of the α-acyloxyamide intermediate. In Chapter III, the Groebke-Blackburn-Bienaymé reaction (GBB-3CR) catalyzed by phosphotungstic acid (HPW) in ethanol and under microwave heating was presented as a greener alternative for the synthesis of imidazo[1,2-a]pyridines. The photophysical properties of these heterocyclics were investigated, revealing high quantum yield values for fluorescence and suggesting an intramolecular charge transfer (ICT) mechanism. The potential herbicidal activity of these compounds was evaluated through in vitro phytotoxicity bioassays, influencing the growth of wheat coleoptiles and three important agricultural seeds (Allium cepa, Lactuca sativa and Solanum lycopersicum). The structure-activity relationship highlighted the importance of halogens in the ortho position of aromatic aldehydes and of the cyclohexyl group of isocyanide. The most active compound was also evaluated against weeds such as Bidens pilosa, Urochloa decumbens and Panicum maximum under hydroponic conditions, demonstrating significant phytotoxic potential. In Chapter IV, thiazolidinone derivatives were prepared via Knoevenagel condensation reaction catalyzed by ethylenediamine (EDA) in acetic acid (AcOH), under microwave heating. The phytotoxicity of these compounds was evaluated in vitro, influencing the growth of etiolated wheat coleoptiles. The results indicated the importance of ortho-substituted aldehydes with electron-withdrawing groups. In addition, new hybrids with the presence of imidazo[1,2-a]pyridines, tetrazoles and α-acyloxyamides were synthesized. In Chapter V, 2-amino-5-arylidene-thiazol-4-one derivatives were synthesized using a multicomponent reaction involving aldehydes, rhodanine and cyclic secondary amines under microwave heating. Mechanistic studies based on NMR and HRMS spectral analyses suggest a two-stage pathway: Knoevenagel condensation followed by sulfur substitution by the amine group. The derivatives were evaluated in bioassays on etiolated wheat coleoptiles. Preliminary results revealed growth-stimulating properties. The methodology was extended to prepare new imidazo[1,2-a]pyridine hybrids.
Unidade Acadêmica:	Instituto de Química (IQ)
Informações adicionais:	Tese (doutorado) — Universidade de Brasília, Instituto de Química, Programa de Pós-Graduação em Química, 2025.
Programa de pós-graduação:	Programa de Pós-Graduação em Química
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Agência financiadora:	Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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