Open AccessA semiempirical study of the conformational behavior of cinchonidine and its interaction with methyl pyruvate
Author(s) -
Donato Alexandre Gomes Aranda,
José Walkimar de M. Carneiro,
Chrystelle Oliveira,
Fábio B. Passos,
Paulo Rogério N. de Souza,
Octávio Augusto Ceva Antunes
Publication year - 2001
Publication title -
brazilian journal of chemical engineering/brazilian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.313
H-Index - 52
eISSN - 1678-4383
pISSN - 0104-6632
DOI - 10.1590/s0104-66322001000300008
Subject(s) - cinchonidine , van der waals force , chemistry , cinchona , computational chemistry , non covalent interactions , potential energy surface , stereochemistry , molecule , catalysis , enantioselective synthesis , organic chemistry , hydrogen bond
Hydrogenation of methyl pyruvate on a palladium or platinum surface in the presence of cinchona alkaloids leads to a high degree of enantiodifferentiation. In the present study, the semiempirical AM1 and PM3 methods are employed to perform a detailed analysis of the conformational behavior of cinchonidine and to study its interaction with methyl pyruvate. Nine different minima were located on the potential energy surface for cinchonidine by both the AM1 and the PM3 methods. Some barriers to interconversion between them are relatively high; however, it is always possible to connect two minima through barriers lower than 3.0 kcal/mol so most of the minima can interact with the substrate. The interaction between cinchonidine and methyl pyruvate was calculated by placing methyl pyruvate near the cinchonidine molecule in different orientations and optimizing the final complex. The calculated interaction energy is lower than 3.5 kcal/moland is predominantly due to van der Waals noncovalent interactions. An analysis of the structure of possible pro-R and pro-S complexes indicates that interaction between cinchonidine and methyl pyruvate alone is not enough to induce enantiodifferentiation