Banca de QUALIFICAÇÃO: PAULO VITOR MATIAS FARIA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : PAULO VITOR MATIAS FARIA
DATE: 10/12/2021
TIME: 08:45
LOCAL: VIDEOCONFERÊNCIA
TITLE:

The Reactivity of N-Oxide Type Pyridines in Selective Amination Reactions with Phosphonium Salts

 

KEY WORDS:

N-oxidetypepyridineamination;2-aminopyrine;Counter-ioneffect; Phosphoniumsalts;Quantumcalculations.

PAGES: 63
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Química Teórica
SUMMARY:

Aminopyridines belong to a class of compounds estimated in organic chemistry, due to their applications in the construction of relevant drugs used in severe clinical conditions, such as in several diseases related to neurological damage reported in the literature. The synthesis of aminopyridines is still a great challenge in organic synthesis, attracting the attention of researchers to the development of strategies that contemplate a selective and high-yield production of these molecules. Currently, a synthetic route for the production of 2-aminopyridines has been highlighted, the procedure contemplates an efficient reaction from phosphonium salts in N-oxide type pyridine amination reactions, proposed by Londegran et al. This work presents a theoretical study focused on this reaction for the production of 2-aminopyridines, and aims to understand the mechanism of formation through software and computational chemistry methods, investigating the structural, energetic and stability properties that lead to the marking of selectivity and spontaneity observed in the bench. These systems were studied using theory-level quantum calculations (M06-2X/6-

331+G(3df,2p), Wb97x-d/6-331+G(3df,2p) and RIJK RI-PWPB95 D3BJ ma-def2 -TZVP def2/JK def2-TZVP/C) based on density functional theory. The mechanism was investigated with the implicit and explicit participation of the counter-ions, suggesting a more adequate profile when considering the ions watching the reaction, similarly the region in which the ion is coupled produces a marking effect on selectivity, it was concluded that the interaction in the CIS position is more effective to drive the expected product, as the choice of ion alters the observed effect. From the analysis of the activation step of pyridine N-oxide, a dependence of some characteristics of the phosphonic additive for reaction continuity was observed, requiring a good leaving group for the activation step to occur, as well as an adequate coordination for that the input region does not become inaccessible.

BANKING MEMBERS:
Presidente - 1859346 - MIGUEL ANGELO FONSECA DE SOUZA
Interno - 1959889 - DAVI SERRADELLA VIEIRA
Interno - 1803692 - FABRICIO GAVA MENEZES