Asymmetric bioreduction of β-ketoesters derivatives by Kluyveromyces marxianus: influence of molecular structure on the conversion and enantiomeric excess.

Simone S.S Oliveira,Francisco R De Aquino-Neto,Luiza R.S Dias,Murilo L Bello,Maria C.K.V Ramos,Carlos R Rodrigues,Sorele B Fiaux,Paula L De Azevedo

doi:10.1590/0001-3765201720170118

Abstract

This study presents the bioreduction of six β-ketoesters by whole cells of Kluyveromyces marxianus and molecular investigation of a series of 13 β-ketoesters by hologram quantitative structure-activity relationship (HQSAR) in order to relate with conversion and enantiomeric excess of β-stereogenic-hydroxyesters obtained by the same methodology. Four of these were obtained as (R)-configuration and two (S)-configuration, among them four compounds exhibited >99% enantiomeric excess. The β-ketoesters series LUMO maps showed that the β-carbon of the ketoester scaffold are exposed to undergo nucleophilic attack, suggesting a more favorable β-carbon side to enzymatic reduction based on adopted molecular conformation at the reaction moment. The HQSAR method was performed on the β-ketoesters derivatives separating them into those provided predominantly (R)- or (S)-β-hydroxyesters. The HQSAR models for both (R)- and (S)-configuration showed high predictive capacity. The HQSAR contribution maps suggest the importance of β-ketoesters scaffold as well as the substituents attached therein to asymmetric reduction, showing a possible influence of the ester group carbonyl position on the molecular conformation in the enzyme catalytic site, exposing a β-carbon side to the bioconversion to (S)- and (R)-enantiomers.

Highlights

Chiral β-hydroxyesters are widely used in the chemical-pharmaceutical industry as intermediates of organic synthesis and some of them have been used for the synthesis of beetle, Lasioderma serricorne (Pilli and Riatto 1998)
Other methods described in the literature leading to the (R)-hydroxyesters (1’b, 3’b, 4’b) requires more laborious and expensive approach, that is the complete inhibition of enzymatic activity for (S)-enantiomer using different microorganisms and growth conditions, recombinant microorganisms or enzyme inhibitors generally toxic and volatile (Ramos et al 2011, Venkataraman and Chadha 2015, Fow et al 2008, Dahl and Madsen 1998, Dao et al 1998, Srivastava et al 2015, Chen et al 2015, Zhang et al 2015)
The results demonstrated that yeast K. marxianus (Oliveira et al 2013, Molinari et al 1999), easy to handle and growth like Saccharomyces cerevisiae, led to the (R)-hydroxyesters (1’b-4’b) without any other additive and in a greater extent than that reported for S. cerevisiae (Zeror et al 2010, Mahmoodi et al 2006)

Summary

Introduction

Chiral β-hydroxyesters are widely used in the chemical-pharmaceutical industry as intermediates of organic synthesis and some of them have been used for the synthesis of beetle, Lasioderma serricorne (Pilli and Riatto 1998). Ethyl 3-hydroxyhexanoate is an important intermediate for the synthesis of (+)-neopeltolide, a potent in vitro antiproliferative agent against the growth of several cancer cell lines and antifungal activity against Candida albicans (Ramos et al 2011, Ghosh et al 2013) Both enantiomeric forms of methyl 3-aryl-3-hydroxypropionates are important building blocks in the synthesis of several chiral drugs, fine chemicals and pesticides (Borowiecki and Bretner 2013, Liu and Liu 2015). The chemical asymmetric methods involve metal catalysts that may leave residues in products and should be avoided for pharmaceuticals Aside from that it generally requires additional steps for protection/deprotection of functional groups and extreme reaction conditions (Hagemann et al 2005, Ng and Jaenicke 2009, Floris et al 2009, Sheldon 2016). The bioreduction occurs under nontoxic and mild reaction conditions (ambient temperature, atmospheric pressure, and aqueous medium) with little impact on the environmental and avoids the burden of groupprotecting procedures (Milner and Maguire 2012, Oliveira et al 2013, Regil and Sandoval 2013, Sheldon 2016)

Methods

Results

Conclusion