Enantioselective reduction of 4-chromanone and its derivatives by selected filamentous fungi

Article abstract of DOI:10.1016/j.molcatb.2013.09.004

Biotransformation of 4-chromanone and its derivatives in the cultures of three biocatalysts: Didymosphaeria igniaria, Coryneum betulinum and Chaetomium sp. is presented. The biocatalysts were chosen due to their capability of enantiospecific reduction of low-molecular-weight ketones (acetophenone and its derivatives and α- and β-tetralone). The substrates were reduced to the respective S-alcohols with high enantiomeric excesses, according to the Prelog's rule. In the culture of Chaetomium sp. after longer biotransformation time an inversion of configuration of the formed alcohols was also observed. The highest yield of transformation was observed for 6-methyl-4-chromanone. In all the tested cultures, the higher was the molecular weight of a chromanone, the lower conversion percent was observed.

Full text of DOI:10.1016/j.molcatb.2013.09.004

Journal of Molecular Catalysis B: Enzymatic 97 (2013) 278–282
Contents lists available at ScienceDirect
Journal of Molecular Catalysis B: Enzymatic
journal homepage: www.elsevier.com/locate/molcatb
Enantioselective reduction of 4-chromanone and its derivatives by
selected filamentous fungi
Tomasz Janeczkoa,∗, Jadwiga Dmochowska-Gładysza,b, Antoni Szumnya,
Edyta Kostrzewa-Susłowa
a Department of Chemistry, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland
b Department of Cosmetology, Wrocław College of Physiotherapy, Ko´sciuszki 4, 50-038 Wrocław, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 7 March 2013
Received in revised form 27 August 2013
Accepted 2 September 2013
Available online 9 September 2013
Biotransformation of 4-chromanone and its derivatives in the cultures of three biocatalysts: Didymo-
sphaeria igniaria, Coryneum betulinum and Chaetomium sp. is presented. The biocatalysts were chosen
due to their capability of enantiospecific reduction of low-molecular-weight ketones (acetophenone and
its derivatives and ␣- and ␤-tetralone). The substrates were reduced to the respective S-alcohols with
high enantiomeric excesses, according to the Prelog’s rule. In the culture of Chaetomium sp. after longer
biotransformation time an inversion of configuration of the formed alcohols was also observed. The
highest yield of transformation was observed for 6-methyl-4-chromanone. In all the tested cultures, the
higher was the molecular weight of a chromanone, the lower conversion percent was observed.
© 2013 Elsevier B.V. All rights reserved.
Keywords:
Biotransformation
Stereoinversion
Enantiospecific reduction
4-Chromanone
Filamentous fungi.
1. Introduction
and simple experimental procedure are the important benefits of
this method, being an interesting alternative to methods using
Enantiomerically pure alcohols play an important role in organic
synthesis. Among others, they are used as chiral building blocks in
synthesis of larger molecules, which are useful in pharmaceutical
industry [1–3].
Enantiopure (S)-chromanol is a synthon of compound CP-
199,331 (Fig. 1), which may find application in treatment of asthma
[4,5]. Chromanol 293B (Fig. 1), a chiral derivative of 4-amino-
2,2-dimethylchromane, is a potential class III antiarrhythmic drug
that inhibits cardiac IKs potassium channels [6,7]. Yang et al. [8]
conclude that the (2)-[3R,4S] enantiomer of chromanol 293B is a
selective inhibitor of KvLQT11minK and therefore a useful tool for
studying IKs.
Enantiopure chiral compounds can be obtained via stereose-
lective reduction (either biological or chemical one) [9–12]. A
method that meets the criteria of green chemistry technology is
an asymmetric reduction of ketones with the help of biocatalysts
[13–16]. Using whole cells of microorganisms of both growing and
resting-state cultures eliminates problems with regeneration of co-
factors cooperating with enzymes [17–19]. Additionally, low costs
synthetic catalysts [20–22]. Using living organisms for organic
synthesis have also some limitations. Metabolic processes are of
complex nature and living biocatalysts have their substrate speci-
ficity, so they are not universal. Therefore, it is important to study
the scope of this type catalyst.
2. Experimental
2.1. Materials
The substrates: 4-chromanone (1a), 6-methyl-4-chromanone
(1b) and 6,7-dimethoxy-2,2-dimethyl-4-chromanone (1d) were
purchased from Sigma–Aldrich. 7-Hydroxy-2,2-dimethyl-4-
chromanone (1e) was obtained in the reaction of resorcinol
with 3-methylbut-2-enoic acid in the presence of zinc chloride.
7-Methoxy-2,2-dimethyl-4-chromanone (1c) was obtained in
the reaction of 7-hydroxy-2,2-dimethyl-4-chromanone (1e) with
methyl iodide (Scheme 1).
All the microorganisms: Didymosphaeria igniaria KCh 6670,
Chaetomium sp. KCh 6651, and Coryneum betulinum KCh 6538 were
isolated from forest environment (south Poland) from dead parts of
leafy plants and identified in the Department of Forest Phytopatho-
logy of the University of Agriculture in Kraków, Poland. The strains
were cultivated on a Sabouraud agar consisting of: aminobac 5 g,
∗
Corresponding author. Tel.: +48 71 320 52 52; fax: +48 71 3284124.
E-mail addresses: janeczko13@interia.pl, tomasz.janeczko@up.wroc.pl
(T. Janeczko).
1381-1177/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molcatb.2013.09.004

T. Janeczko et al. / Journal of Molecular Catalysis B: Enzymatic 97 (2013) 278–282
279
F
SO2
F
N
O
OH
O
N
O
O
NC
OH
S
NHSO2CF3
CP-199,331
Chromanol 293B
Fig. 1. Biologically active chromanol derivatives.
Scheme 1. Synthesis of 7-Methoxy-2,2-dimethyl-4-chromanone (1c).
peptone K 5 g, glucose 40 g and agar 15 g in 1 l of distilled water at
28 ◦C and pH 5.5 and stored in refrigerator at 4 ◦C.
120 ◦C (1 min), gradient 0.4 ◦C/min to 135 ◦C, gradient 30 ◦C/min to
200 ◦C (3 min) tR (R) 17.7 min, tR (S) 18.6 min; for 2c: Supelco Gama
DEXTM225, Fused Silica 30 m × 0.25 mm × 0.25 ␮m; temperature
program 145 ◦C (1 min), gradient 1.5 ◦C/min to 165 ◦C, gradient
30 ◦C/min to 200 ◦C (3 min) tR (R) 7.5 min, tR (S) 7.9 min and for 2d:
Supelco Gama DEXTM225, Fused Silica 30 m × 0.25 mm × 0.25 ␮m;
temperature program 145 ◦C (1 min), gradient 1.5 ◦C/min to 170 ◦C,
gradient 30 ◦C/min to 200 ◦C (3 min) tR (R) 13.6 min, tR (S) 13.9 min)
was used to determinate the composition and enantiomeric
excesses of product mixtures. Authentic reference samples of the
racemic alcohol were prepared by reducing the ketones with
sodium borohydride in methanol. The NMR spectra were recorded
on a DRX 300 MHz Bruker spectrometer and measured in CDCl3.
Optical rotations were measured on an Autopol IV automatic
polarimeter (Rudolph). The absolute configuration of the products
was determined by comparison of their optical rotation value with
literature data.
2.2. Alcohol reference standards
Reference standards of racemic alcohols were obtained by
reduction of 4-chromanone (1a) and 6-methyl-4-chromanone (1b)
with NaBH4. Whereas, under the same conditions 2,2-dimethyl-4-
chromanones gave the products of alcohol dehydration (Scheme 2).
The desired products (alcohols) were achieved by cooling the reac-
tion mixture to 0 ◦C and using the alkaline solution to decompose
the catalyst.
2.3. Analytical methods
The course of biotransformation was controlled by means of
TLC. Analytical TLC was carried out on silica gel G 60 F254 plates
(Merck). Chromatograms were developed using hexane/acetone
mixture (3:1, v/v) as the eluent. Compounds were detected by
spraying the plates with 1% Ce(SO4)2 and 2% H3[P(Mo3O10)4] in 10%
H2SO4. Products were separated by column chromatography using
silica gel (SiO2, Kieselgel 60, 230–400 mesh, 40–63 ␮m, Merck) and
hexane/acetone mixture (3:1, v/v) as the developing system. Com-
position of biotransformation mixtures was established by GC. GC
analysis was performed using a Hewlett-Packard 5890A (Series II)
GC instrument fitted with a flame ionization detector (FID). The chi-
ral, capillary column (for 2a: Supelco Beta DEXTM225, Fused Silica
30 m × 0.25 mm × 0.25 ␮m; temperature program 120 ◦C (1 min),
gradient 0.4 ◦C/min to 131 ◦C, gradient 30 ◦C/min to 200 ◦C (3 min)
tR (R) 13.0 min, tR (S) 14.1 min; for 2b: Supelco Gama DEXTM225,
Fused Silica 30 m × 0.25 mm × 0.25 ␮m; temperature program
2.4. Screening procedure
Erlenmeyer flasks (300 ml), each containing 100 ml of the
medium consisting of 3 g glucose and 1 g aminobac dissolved in
water, were inoculated with a suspension of microorganisms and
then incubated for 3–7 days at 25 ◦C on a rotary shaker (190 rpm).
After full growth of the culture (about 12 g of cell dry weight/l) 20,
40, 60, 80 and 100 mg of a substrate dissolved in 1 ml of acetone
was added. After 1, 3, 6 and 9 days of incubation under the above
conditions, portions of 10 ml of the transformation mixture were
taken out and extracted with CHCl3 (3× 10 ml). The extracts were
dried over MgSO4, concentrated in vacuo and analyzed by GC. All
the experiments were repeated three times.
2.5. Preparative biotransformation
The same transformations were performed on the preparative
scale in 2000 ml flasks, each containing 500 ml of the cultivation
medium. The cultures were incubated under the same conditions
and then 200 mg of substrate dissolved in 2 ml of acetone was
added to the grown D. igniaria culture (the strain selected for
detailed studies). After 6 days of incubation the mixtures were
extracted with CHCl3 (3× 300 ml), dried (MgSO4) and concentrated
in vacuo. The transformation products were separated by column
chromatography and analyzed (TLC, GC, 1H NMR).
Scheme 2. Reduction of 2,2-dimethyl-4-chromanones in room temperature.

280
T. Janeczko et al. / Journal of Molecular Catalysis B: Enzymatic 97 (2013) 278–282
2.6. Identification of products
O
OH
O
1R
2R
1 R
Structures of the biotransformation products were confirmed
by 1H NMR. The absolute configuration of the products was deter-
mined by comparison of their optical rotation value with literature
data.
microbial
reduction
R3
R4
R3
R4
2 R
O
2
1
(S)-chroman-4-ol (2a): pale yellow oil; [␣]D23 = −47.6◦ (c 1.8,
CHCl3) (73% ee) (lit. [␣]D25 = −66.0◦ (c = 3.03, CHCl3), 97% ee [23].
1H NMR (300 MHz, CDCl3) ı (ppm): 1.84 (br s, 1H; OH), 2.02 (m,
1H, H-3), 2.10 (m, 1H, H-3), 4.26 (m, 2H, H-2), 4.78 (t, 1H, J = 4.0 Hz,
H-4a), 6.83 (d, 1H, J = 7.8 Hz; H-8), 6.91 (t, 1H, J = 7.8 Hz, H-6), 7.20
(td, 1H, J = 7.8, 1.6 Hz; H-7), and 7.32 (dd, 1H, J = 7.8, 1.6 Hz, H-5).
(S)-6-methylchroman-4-ol (2b): pale yellow oil; [␣]D23 = −20.5◦
(c 0.9, CHCl3) (63% ee) (lit. [␣]D23 = −38.6◦ (c = 1.50, CHCl3), 100% ee
[24]. 1H NMR (300 MHz, CDCl3) ı (ppm): 1.85 (s, 1H, OH); 2.00 (m,
1H, H-3); 2.09 (m, 1H, H-3); 2.26 (s, 3H, CH3), 4.22 (m, 2H, H-2),
4.74 (t, 1H, J = 4.0 Hz, H-4a), 6.72 (d, 1H, J = 8.3 Hz, H-8), 6.91 (dd, 1H,
J = 8.3, 2.0 Hz, H-7), and 7.10 (d, 1H, J = 2.0 Hz, H-5).
1a
1b
1c
1d
1e
2a
2b
2c
2d
2e
1R = H
1R = H
1R = H
2R = H
3R = H
4R = H
2R = CH3
3R = H
4R = H
2R = OCH3
2R = OCH3
2R = OH
3R = CH3
3R = CH3
3R = CH3
4R = CH3
4R = CH3
4R = CH3
1R = OCH3
1R = H
Scheme 3. Microbial reduction of selected 4-chromanones.
7-methoxy-2,2-dimethylchroman-4-one (1c): pale yellow
powder; 1H NMR (300 MHz, CDCl3) ı (ppm): 1.43 (s, 6H, 2 x CH3),
2.64 (s, 2H, H-3), 3.81 (s, 3H, OCH3), 6.35 (d, 1H, J = 2.4 Hz, H-8),
6.55 (dd, 1H, J = 2.4, 8.8 Hz, H-6), and 7.81 (d, 1H, J = 8.8 Hz, H-5).
7-methoxy-2,2-dimethylchrom-3-ene (3c) (elimination prod-
uct): colorless oil; 1H NMR (300 MHz, CDCl3) ı (ppm): 1.41 (s, 6H,
CH3), 3.79 (s, 3H, OCH3), 5.45 (d, 1H, J = 9.7 Hz, H-3), 6.30 (d, 1H,
J = 9.7 Hz, H-4), 6.36 (d, 1H, J = 2.45 Hz, H-8), 6.43 (dd, 1H, J = 2.45,
8.2 Hz, H-6), and 6.91 (d, 1H, J = 8.2 Hz, H-5).
(S)-7-methoxy-2,2-dimethylchroman-4-ol (2c): pale yellow
powder; [␣]D23 = −23.0◦ (c 1.4, CHCl3) (93% ee) (lit. (R)-1c,
[␣]D25 = +22.1◦ (c = 0.72, CHCl3, 100% ee (S) [25]. 1H NMR (300 MHz,
CDCl3) ı (ppm): 1.31 (s, 3H, CH3), 1.45 (s, 3H, CH3), 1.84 (dd, 1H
J = 13.5, 8.3 Hz, H-3), 1.98 (s, 1H, OH), 2.14 (dd, 1H J = 13.5, 6.1 Hz,
H-3), 3.75 (s, 3H, OCH3), 4.79 (dd, 1H, J = 8.3, 6.1 Hz, H-4a), 6.33
(d, 1H, J = 2.5 Hz, H-8), 6.51 (dd, 1H, J = 8.5, 2.5 Hz, H-6), and 7.33 (d,
1H, J = 8.5 Hz, H-5).
Fig. 2. Time dependence of transformation of 4-chromanone (1a) in Chaetomium
sp. KCh 6651 culture.
6,7-dimethoxy-2,2-dimethylchrom-3-ene (3d) (elimination
product): colorless needles; 1H NMR (300 MHz, CDCl3) ı (ppm):
1.40 (s, 6H, CH3), 3.85 (s, 3H, OCH3), 3.86 (s, 3H, OCH3), 5.48
(d, 1H, J = 9.7 Hz, H-3), 6.27 (d, 1H, J = 9.7 Hz, H-4), 6.44 (s, 1H, H-8),
and 6.56 (s, 1H, H-5).
(S)-6,7-dimehtoxy-2,2-dimethylchroman-4-ol (1d): colorless
needles; [␣]D23 = −36.40◦ (c = 0.64, CHCl3) (75% ee); 1H NMR
(300 MHz, CDCl3) ı (ppm): 1.30 (s, 3H, CH3), 1.42 (s, 3H, CH3),
1.82 (dd, 1H, J = 13.5, 8.3 Hz, H-3), 2.14 (dd, 1H, J = 13.5, 6.1 Hz, H-3),
3.80 (s, 3H, OCH3), 3.83 (s, 3H, OCH3), 4.78 (dd, 1H, J = 8.3, 6.1 Hz,
H-4a), 6.35 (s, 1H, H-8), and 6.92 (s, 1H, H-5).
reduction occurs, giving the S-alcohol (2b) with low enantioselec-
tivity, and then this enantiomer is selectively oxidized back to the
substrate. As a result, after nine days of biotransformation (R)-6-
methyl-4-chromanol is obtained as a single product (Scheme 4).
For substrate 1c (7-mehtoxy-2,2-dimethyl-4-chromanone) the
reaction pattern is not the same, however one can observe that
the content of the R enantiomer is continuously increasing with
time, whereas the amount of the S-alcohol (2c) drops (Fig. 4). These
indicate that with longer reaction time it is possible to achieve an
enantiomeric excess of the R-alcohol. In the culture of Chaetomium
3. Results and discussion
The strains of D. igniaria, C. betulinum and Chaetomium sp. were
chosen as biocatalysts, due to their capability to enantiospecific
reduction of low-molecular-weight ketones [18,26–29].
The only microorganism that transformed four of the substrates
was D. igniaria. In each case a considerable enantiomeric excess of
S-alcohol was observed in the product mixture (Scheme 3, Table 1).
The results of biotransformations performed in the culture
of Chaetomium sp.1 are interesting mainly with respect to com-
position of the product mixture. In the case of substrates 1a
(4-chromanone) and 1b (6-methyl-4-chromanone), after one day
of biotransformation the respective S-alcohols predominated, but
when the reaction was carried out longer, the content of the
R-alcohols gradually increased. After three days it was the R enan-
tiomer that prevailed (Figs. 2 and 3).
The observation of 6-methyl-4-chromanone (1b) transforma-
tion process led to the conclusion that at first the carbonyl group
Fig. 3. Time dependence of transformation of 6-methyl-4-chromanone (1b) in
Chaetomium sp. KCh 6651 culture.

T. Janeczko et al. / Journal of Molecular Catalysis B: Enzymatic 97 (2013) 278–282
281
Table 1
Microbial reduction of 4-chromanone and its derivatives.
Substrate
Microorganism
Reaction time [days]
Substrate conversion [%]
Product (alcohol)
Ee [%]
Configuration
Didymosphaeria igniaria
Chaetomium sp.1
Coryneum betulinum
Didymosphaeria igniaria
Chaetomium sp.1
Coryneum betulinum
Didymosphaeria igniaria
Chaetomium sp.1
Coryneum betulinum
Didymosphaeria igniaria
Chaetomium sp.1
3
3
6
6
9
3
9
1
9
6
9
9
9
9
9
100
89
65
98
100
93
56
75
0
50
0
0
0
0
73
19
88
63
100
96
93
84
–
75
–
–
–
–
S
R
S
S
R
S
S
S
–
S
–
–
–
–
–
1a
1b
1c
1d
1e
Coryneum betulinum
Didymosphaeria igniaria
Chaetomium sp.1
Coryneum betulinum
0
–
OH
OH
O
O
different final results of reduction of 1a, 1b and 1c). The analo-
gous changes in products composition were described in our earlier
work [29].
Among all the tested microorganisms the strain C. betulinum
transformed the least number of substrates. Nevertheless, the
yields and the enantiomeric excesses of products for this microor-
ganism were satisfying. Transformation of 4-chromanone (1a) and
6-methyl-4-chromanone (1b) by means of C. betulinum gave the
respective S-alcohols, in accordance with the Prelog’s rule.
For the strains C. betulinum i Chaetomium sp.1 the presence of
an additional methyl group in a xenobiotic molecule (substrate
1b) increased the percent of substrate conversion, as well as the
enantiomeric excess of resulting alcohol. Whereas, in the culture
of D. igniaria it was 4-chromanone (1a) that was reduced with
much higher yield compared to 6-methyl-4-chromanone (1b) and
the resulting 4-chromanol (2a) was of much higher enantiomeric
excess than its methyl derivative (2b).
The presence of methyl groups in the non-aromatic ring of
the other substrates (1c–1e) had decreasing effect on the reaction
yield. This was probably because of the steric hindrance associated
with these substituents. 6-Hydroxy-2,2-dimethyl-4-chromanone
(1e) was reduced by neither of the tested microorganisms.
The effect of size of substituents on effectiveness of micro-
bial conversion of aliphatic-aromatic ketones was described by
Carballeira et al. [30]. Another paper on this topic concerns bio-
transformations of aliphatic-aromatic ketones by the strain D.
igniaria KCh 6670. Also in this case a considerable decrease in
substrate conversion was observed for the following substrates:
acetophenone, tetralone and 9,10-phenantrene (0%) [18].
O
O
1b
(R)-2b
(S)-2b
Scheme 4. Transformation of 6-methyl-4-chromanone (1b) in the culture of
Chaetomium sp. KCh 6651.
sp. KCh 6651 substrate 1c is transformed in analogous way to sub-
strates 1a and 1b, but the process is much slower. This is probably
due to the presence of additional substituents in the structure of
1c, compared to 1a and 1b, which make it less compatible with the
active site of the dehydrogenases present in this microorganism.
Further confirmation of this conclusion is a complete lack of bio-
transformation products for substrates 1d and 1e incubated in the
culture of this strain.
During incubation of substrates 1a, 1b and 1c in the culture of
Chaetomium sp. KCh 6651 there are continuous processes of ketone
reduction to both S and R-alcohols and oxidation of the formed alco-
hols back to the ketones. These four competitive processes proceed
with different speed, changing during the biotransformation time
(induction of dehydrogenases by substrates and products). Even a
small change in speed of one of the competitive processes leads
to a complete change in composition of the reaction mixture (and
Acknowledgments
This research was supported financially by the European Union
within the European Regional Development Found (grant no.
POIG.01.03.01-00-158/09-06).
References
[1] K. Goldberg, K. Schroer, S. Lütz, A. Liese, Appl. Microbiol. Biotechnol. 76 (2007)
249.
[2] R. Wohlgemuth, Curr. Opin. Microbiol. 13 (2010) 283.
[3] D.M. Solano, P. Hoyos, M.J. Hernáiz, A.R. Alcántara, J.M. Sánchez-Montero, Biore-
sour. Technol. 115 (2012) 196.
[4] A.V. Kuperman, A.S. Kalgutkar, A. Marfat, R.J. Chambers, T.E. Liston, Drug Metab.
Dispos. 29 (2001) 1403.
[5] R.J. Chambers, A. Marfat, G.W. Antognoli, J.B. Cheng, D.B. Damon, A.V. Kuper-
man, T.C. Liston, C. Mebus, J.S. Pillar, J.T. Shirley, J.W. Watson, Bioorg. Med.
Chem. Lett. 9 (1999) 2773.
[6] J. Schreieck, Y. Wang, V. Gjini, M. Korth, B. Zrenner, A. Schomig, C. Schmitt, J.
Cardiovasc. Electrophysiol. 8 (1997) 1420.
Fig. 4. Time dependence of transformation of 6-methoxy-2,2-dimethyl-4-
chromanone (1c) in Chaetomium sp. KCh 6651 culture.

282
T. Janeczko et al. / Journal of Molecular Catalysis B: Enzymatic 97 (2013) 278–282
[7] C. Lerce, I. Bruhova, H. Lerce, K. Steinmeyer, A.D. Wei, N. Strutz-Seebohm, F.
Lang, A.E. Busch, B.S. Zhorov, G. Seebohm, Mol. Pharmacol. 71 (2007) 1503.
[20] M.A. Quezada, J.D. Carballeira, J.V. Sinisterra, Bioresour. Technol. 112 (2012)
18.
[8] I.C.-H. Yang, M.W. Scherz, A. Bahinski, P.B. Bennett, K.T. Murray, J. Pharmacol.
Exp. Ther. 294 (2000) 955.
[21] G.W. Huisman, J. Liang, A. Krebber, Curr. Opin. Chem. Biol. 14 (2010) 122.
[22] E.B. Kurbanoglu, K. Zilbeyaz, N.I. Kurbanoglu, Tetrahedron-Asymmetry 22
[9] E.J. Corey, R.K. Bakshi, S. Shibata, J. Am. Chem. Soc. 109 (1987) 5551.
[10] K. Nakamura, R. Yamanaka, T. Matsuda, T. Harada, Tetrahedron-Asymmetry 14
(2003) 2659.
(2011) 345.
[23] C.V. Ursini, G.H.M. Dias, J.A.R. Rodrigues, J. Organomet. Chem. 690 (2005)
3176.
[11] Y. Kawanami, K. Hoshino, W. Tsunoi, Tetrahedron-Asymmetry 22 (2011) 1464.
[12] J. Wettergren, A. Bøgevig, M. Portier, H. Adolfsson, Adv. Synth. Catal. 348 (2006)
1277.
[24] I. Bichlmaier, A. Siiskonen, M. Finel, J. Yli-Kauhaluoma, J. Med. Chem. 49 (2006)
1818.
ˇ
[25] M. Majeric´, M. Gelo-Pujic´, V. Sunjic´, A. Lévai, P. Sebök, T. Timàr, Tetrahedron-
[13] W.-Y. Lou, W. Wang, T.J. Smith, M.-H. Zong, Green Chem. 11 (2009) 1377.
[14] Z.-H. Yang, L. Luo, X. Chang, W. Zhou, G.-H. Chen, Y. Zhao, Y.-J. Wang, J. Ind.
Microbiol. Biotechnol. 39 (2012) 835.
Asymmetry 6 (1995) 937.
[26] T. Janeczko, J. Dmochowska-Gładysz, M. Kuz´bik, T. Kowalski, Chem. Agric. 7
(2006) 181.
[15] G. Aina, G. Nasini, O.V. de Pava, J. Mol. Catal. B: Enzym. 11 (2001) 367.
[16] M. Furuta, M. Shoji, T. Ugai, J. Mol. Catal. B: Enzym. 82 (2012) 8.
[17] E.B. Kurbanoglu, K. Zilbeyaz, N.I. Kurbanoglu, H. Kilic, Tetrahedron-Asymmetry
18 (2007) 1159.
[27] T. Janeczko, J. Dmochowska-Gładysz, E. Kostrzewa-Susłow, Przem. Chem. 88
(2009) 458.
[28] T. Janeczko, J. Dmochowska-Gładysz, E. Kostrzewa-Susłow, World J. Microbiol.
Biotechnol. 26 (2010) 2047.
´
´
[18] A. Swizdor, T. Janeczko, J. Dmochowska-Gładysz, J. Ind. Microbiol. Biotechnol.
[29] T. Janeczko, A. Panek, A. Swizdor, J. Dmochowska-Gładysz, E. Kostrzewa-
37 (2010) 1121.
Susłow, Curr. Microbiol. 65 (2012) 189.
[19] E. Kyslíková, P. Babiak, H. Maresˇová, A. Palyzová, J. Hájícˇek, P. Kyslík, J. Mol.
[30] J.D. Carballeira, M. Valmaseda, E. Alvarez, J.V. Sinisterra Gago, Enzyme Microb.
Technol. 34 (2004) 611.
Catal. B: Enzym. 67 (2010) 266.