Banca de DEFESA: JORDAN KERVEN PATRÍCIO DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JORDAN KERVEN PATRÍCIO DA SILVA
DATE: 13/10/2020
TIME: 14:00
LOCAL: Remotamente pelo Google Meet
TITLE:

2,3-Dichloro-6,7-dinitroquinoxaline as a chemodosimeter for the detection of L-cysteine in aqueous medium

KEY WORDS:

: L-cysteine; 2,3-dichloro-6,7-dinitroquinoxaline; chemodosimeter; UV-Vis spectroscopy; 2,3-dicloro-6,7-dinitroquinoxaline; selective sensing.

 

PAGES: 50
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Físico-Química Orgânica
SUMMARY:

Amino acids are key species in several biological processes due their role as building block for the synthesis of proteins as well as other biological functions. L-cysteine is an essential proteic amino acid, and beside other functions, acts effectively in active site of enzymes and as glutathione precursor. Due its relevance, Cys has became an interesting target for the development pf molecular systems able to detect it. This work reports the use of 2,3-dichloro-6-7dinitroquinoxaline (DCDNQX) as a functional chemodosimeter for detection of Cys in aqueous solution based on nucleophilic aromatic substitution (SNAr). DCDNQX was synthetized in good overall yield (65%) via a sequential three-step protocol. UV-Vis spectroscopy analysis indicated that DCQNQX reacts selectively with Cys over other selected amino acids (tyrosine (Tyr), alanine (Ala), lysine (Lys), Histidine (His) and glutamic acid (Glu)) in DMF-H₂O 5:1 v/v solution in the presence of K₂CO₃. This behavior is justified by the higher nucleophilicy of tiolate over phenols and amines in SNAr reactions. Selective sensing was based on the band at 275 nm that emerges in the reaction between DCDNQX and Cys after 20 minutes. At this moment, the products from reaction of DCQNQX and Cys are under characterization in attempt to understand the whole mechanisms involved in the detection of this relevant amino acid.

 

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