Banca de DEFESA: FERNANDO ALVES BARRETTO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : FERNANDO ALVES BARRETTO
DATE: 03/04/2024
TIME: 08:00
LOCAL: Sala de Seminários do IQ
TITLE:

 

 

clear

 

 

 

 

 

 

 

 

 

120 / 5.000

 

Resultados de tradução

Resultado da tradução

SYNTHESIS OF FUNCTIONALIZED COUMARINS VIA NOVOFORMAL [4+2] OXA-CYCLOADDITION PATTERN OFMALEIMIDES WITH 2-HYDROXYALDEHYDES

KEY WORDS:

coumarines, heterocycle, maleimides

PAGES: 150
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Síntese Orgânica
SUMMARY:

In this work, we conducted an unprecedented study of the synthetic applications
of substituted coumarins via the formal oxa-[4+2] cycloaddition reaction of 2-
hydroxy-aldehydes and maleimides. Forty-six new coumarin and itaconimide
were obtained, with 7% to 68% yields. In the applications of formal cycloaddition
reactions using maleimides, a new pattern of ambiphilic (C,O) reactivity was
discovered, given that the applications of maleimides in Diels-Alder and
binucleophilic (N,N), (N,C), (N,S), (N,O) cycloaddition reactions are already
known. An unprecedented methodological transposition was developed, using
continuous flow, and coumarins were obtained with yields between 40% and
63%. The photophysical study showed that the angular coumarins exhibited
fluorescence when excited at a wavelength of 200 nm. Only four coumarins
(118z), (118af), (118ac), and (118ag) showed emission at wavelengths in the
405-436 nm range, while the others exhibited no emission at this excitation.
Coumarin (118ag) displayed a bathochromic shift in the visible region, while
coumarins (118z), (118af), and (118ac) showed an ipsochromic shift in the visible
region. The presence of withdrawing substituents on the maleimide ring led to
emission in the 405-436 nm region, whereas with donor groups, we observed no
emission

COMMITTEE MEMBERS:
Presidente - 1215450 - SILVIO DO DESTERRO CUNHA
Interno - 2166886 - ANDRE ALEXANDRE VIEIRA
Interno - 1068075 - JORGE MAURICIO DAVID
Interna - 1490845 - VALERIA BELLI RIATTO
Externo à Instituição - KLEBER THIAGO OLIVEIRA - UFSCAR
Externa à Instituição - FERNANDA ANDREIA ROSA - UEM
Externa à Instituição - FERNANDA GADINI FINELLI - UFRJ