Banca de DEFESA: LUCIANO PEGUINI DE SOUSA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LUCIANO PEGUINI DE SOUSA
DATE: 03/03/2023
TIME: 13:30
LOCAL: remoto
TITLE:

ASYMMETRIC CATALYTIC PROCESSES APPLIED IN A O-MICHAEL-ALDOL REACTIONS EMPLOYNG L-AMINO ACIDS AND ENZYMES DERIVATIVES

KEY WORDS:

Asymmetric catalysis, Organocatalysis, Biocatalysis, Chromenes.

PAGES: 118
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Síntese Orgânica
SUMMARY:

Asymmetric catalysis is an interesting way to obtain enantiomerically pure compounds or with high enantiomeric purity. Asymmetric catalysis techniques have been modernized and expanded in the last 20 years. Modern synthetic methodologies seek to reconcile agility, low cost and minimal environmental impacts. Asymmetric catalysis is divided into three main areas: organocatalysis, biocatalysis and metallic catalysis. This work focused on the synthesis of chromenes (benzopyrans) through organocatalysis and biocatalysis of the oxa-Michael-aldol reaction of nitrostyrene or cinnamaldehyde with salicylaldehyde. Chromenes are heterocycles with a basic nucleus consisting of a pyran ring fused to a benzene ring (bicyclic). They are important molecules for several industrial branches, but mainly the pharmaceutical one. Chiral drugs occupy a prominent place in the industry due to their ability to selectively interact with enzymes or with a stereospecific biological receptor (chiral macromolecules), thus provoking a biological response. Through organocatalysis, using thiazolidines (3a and 3b) and L-proline derivative (4) under different conditions, it was attempted to synthesize compounds 1a and 1b, with enantiomeric excess. The results showed that for the conditions and compounds tested, it is not possible to synthesize molecules with enantiomeric excess. With the use of enzymes (biocatalysis), CAL-B and α-amylase, attempts were made to synthesize compounds 1a and 1b, 2a and 2b with enantiomeric excess, once again without success. Both in the organocatalysis and in the biocatalysis of the chromene derivatives that were tried to synthesize, the enantiomeric excess was unsuccessful, this may be related to non-activation of the nucleophile and electrophile or lack of induced orientation of the olefin during the transition step.

BANKING MEMBERS:
Externo à Instituição - GIULIANO CESAR CLOSOSKI - USP
Interno - 1805937 - JEFFERSON LUIZ PRINCIVAL
Presidente - 1675886 - JOSE AUGUSTO FERREIRA PEREZ VILLAR