Enantioselective Dynamic Process Reduction of a -and b -Tetralone and Stereoinversion

of Resulting Alcohols in a Selected Strain Culture

Tomasz Janeczko •Anna Panek •

Alina S

´wizdor •Jadwiga Dmochowska-Gładysz •

Edyta Kostrzewa-Susłow

Received:20November 2011/Accepted:25April 2012/Published online:22May 2012ÓThe Author(s)2012.This article is published with open access at http://www.1mpi.com

Abstract a -Tetralone and b -tetralone were subjected to biotransformation by 14fungal strains.Enantiomeric purity of the products depended on the reaction time.3-Day transformation of a -tetralone in Absidia cylindrospora culture gave S -(?)-1,2,3,4-tetrahydro-1-naftol of 92%ee,whereas longer biotransformation time resulted in decrease of ee value.3-Day transformation of b -tetralone by the same strain gave predominantly S -(-)-1,2,3,4-tetrahydro-2-naftol,whereas after 9days of the reaction,the R -enan-tiomer with 85%ee was isolated.Transformation of b -tetralone by Chaetomium sp .KCh 6651gave pure (S )-(-)-1,2,3,4-tetrahydro-2-naftol in high yield at the con-centration of 1g/l.In this process,a non-selective carbonyl reduction was observed,followed by a selective oxidation of the R -alcohol.

Introduction

Enantiomerically pure alcohols are useful chiral building blocks for asymmetric synthesis of bioactive compounds of complicated structures [9,12,22,24].For this reason,studies on effective way of their production on a pre-parative scale are undertaken.An asymmetric reduction of ketones using biocatalysts is a method that fulfills green

chemistry requirements [6,14,20].Employment of intact

microorganisms’cells,of both growing and resting-state cultures,eliminates problems with regeneration of co-fac-tors cooperating with enzymes.Low costs and simplicity of the experimental procedure make microbial reduction of carbonyl group an interesting alternative to methods which use synthetic catalysts [4].

In order to find new biocatalysts that are capable to reduce enantiospecifically the aliphatic–aromatic ketones,we checked several strains of filamentous fungi and yeasts.We have chosen a -(1)and b -tetralone (3)as substrates for the tests because products of their reduction are used as chiral synthons in pharmaceutical industry [7,23,26].(S )-a -Tetralol ((S )-2)is a substrate in synthesis of antidepres-sant medicines [21,23],whereas enantiomerically pure (S )-b -tetralol ((S )-4)and its hydroxy and alkoxy derivatives may be employed in synthesis of 2-aminotetralins,the compounds which express activity toward dopamine,serotonin,and melatonin receptors [7,26].The substituted (S )-b -tetralol is a precursor of a drug used in cardiac arrhythmia [15,18,26].Analogs of 2-aminotetralin have been used in the synthesis of drugs for the treatment of many central nervous system-related disorders [3]and in the synthesis of antifungal agents [25].

Experimental Materials

The substrates:a -tetralone (1)and b -tetralone (3)were purchased from Sigma-Aldrich.All the microorganisms:Coryneum betulinum KCh 6534,Absidia cylindrospora KCh 336,Saccharomyces brasiliensis KCh 905,Chaeto-mium sp .KCh 6651,Chaetomium sp .KCh 6665,Absidia

T.Janeczko (&)ÁA.Panek ÁA.S

´wizdor ÁJ.Dmochowska-Gładysz ÁE.Kostrzewa-Susłow Department of Chemistry,Wrocław University of

Environmental and Life Sciences,Norwida 25,50-375Wrocław,Poland

e-mail:janeczko13@interia.pl

J.Dmochowska-Gładysz

Department of Cosmetology,Wrocław College of

Physiotherapy,Kos

´ciuszki 4,50-038Wrocław,Poland 123

Curr Microbiol (2012)65:189–194DOI 10.1007/s00284-012-0143-2