Banca de DEFESA: ERIVALDO PAULINO DA COSTA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ERIVALDO PAULINO DA COSTA
DATA : 21/01/2019
HORA: 10:00
LOCAL: Auditório do Química III
TÍTULO:

Multicomponent synthesis of substituted 3-styryl-1H-quinoxaline-2-ones in aqueous medium

PALAVRAS-CHAVES:

multicomponent reactions; green chemistry; 3-styryl-1H-quinoxaline-2-one.

PÁGINAS: 70
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Síntese Orgânica
RESUMO:

Nitrogen heterocycles compounds are of great relevance due their applications in many scientific areas, notably in the development of new materials of technological interest, as well as therapeutic agents and other biological active compounds. Recently, application of green chemistry concepts highlighted the relevance of multicomponent reactions (MCR) in aqueous medium to organic synthesis. This work reports the synthesis of 3-styryl-1H-quinoxaline-2-one-based nitrogen heterocycles (SQXO) based in MCR protocol in aqueous medium. The tri-component systems, which involves reaction of o-phenylenediamine sodium pyruvate and different aldehydes, were carried out in 20% aqueous acetic acid, and in the presence of sodium acetate. Fourteen SQXO derivatives, including eight new compounds, were obtained in 65-92% in 8-14 hours. Products were properly characterized by melting point as well as infrared and nuclear magnetic resonance (¹H and ¹³C) spectroscopies. Reactions are supposed to proceed via mechanism involving initial condensation of aromatic diamine and sodium pyruvate, to afford 3-methyl-1H­-quinoxaline-2-one, which reacts with different aldehydes via aldol-type condensation. It is important to point out that only water molecules are released to the medium during all stages. This green synthetic protocol becomes especially attractive due the applications of SQXO derivatives in many areas, notably those associated to biological and material fields.

MEMBROS DA BANCA:
Presidente - 1803692 - FABRICIO GAVA MENEZES
Interna - 1149440 - ROSANGELA DE CARVALHO BALABAN
Externo à Instituição - RODRIGO CRISTIANO - UFPB