1514
Candida tropicalis CE017: a New Brazilian Enzymatic Source
J. Braz. Chem. Soc.
0.5 at 600 nm to obtain a suspension of 32 × 106 CFU mL-1
determined by counting of colony forming units (CFU) on
PotatoAgar Plates.An aliquot of 1.0 mL of this suspension
was inoculated in 250 mL Erlenmeyer flask containing
100 mL of Potato broth to produce biomass. When Peptone/
Dextrose was used as medium the counting of CFU was
15 × 106 CFU mL-1. In the case of Czapeck medium the
CFU value was 57 × 103 CFU mL-1.
tR 23.9 (S) min. Column AS. [α]D25 = +29.8, c 0.4, CHCl3,
for 99% ee of (S)-enantiomer.21
(S)-1-(3-Nitrophenyl)ethanol, 3b
1H NMR (CDCl3, 300.13 MHz): d 1.47 (3H, d, J 6.6 Hz,
H2), 4.96 (1H, q, J 6.6 Hz, H1), 7.47 (1H, t, J 7.8 Hz, H5’),
7.67 (1H, d, J 7.8 Hz, H6’), 8.04 (1H, ddd, J 8.3, 2.1 and
0.9 Hz, H4’), 8.18 (1H, t, J 1.8 Hz, H2’); 13C NMR (CDCl3,
75.5 MHz): d 25.2 (C2), 69.1 (C1), 120.2 (C4’), 122.1 (C2’),
129.3 (C5’), 131.6 (C6’), 147.8 (C1’), 148.1 (C3’). Conditions
for determination of the conversion by GC: Injector 225 oC,
Detector 250 oC, 80 oC (5 oC min-1) 180 oC (0 min), tR (3a)
9.5 min and tR (3b) 11.4 min. Column HP-1. Conditions
for determination of the ee by HPLC: 0.8 mL min-1,
hexane:IPA (90:10), 20 ºC, tR 12.8 min (S) and tR 14.2 (R)
min. Column OB-H. [α]D25 = -34.9, c 0.5 CH2Cl2, for 99%
ee of (S)-enantiomer.22
Procedure for the bioreduction of acetophenone and its
derivatives using Candida tropicalis
The growing cells of C. tropicalis CE017 were
used for bioreduction reactions according literature
procedure.19 Then, 20 mg of substrate were added into
erlenmeyer flask and the reactions were shaken for 9
days of reaction. The content of each flask was saturated
with sodium chloride, and then the aqueous phase was
extracted with EtOAc (3 × 80 mL). The organic phase
was dried over with Na2SO4 and then the solvent was
evaporated under reduced pressure. The reaction crude
was analyzed by the appropriate condition and purified by
flash chromatography. All the bioreduction experiments
were done in triplicate.
(S)-1-(4-Nitrophenyl)ethanol, 4b
1H NMR (CDCl3, 300.13 MHz): d 1.50 (3H, d, J 6.6 Hz,
H2), 5.01 (1H, q, J 6.6 Hz, H1), 7.53 (2H, d, J 8.7 Hz,
H2’+ H6’), 8.17 (2H, d, J 8.7 Hz, H3’ + H5’); 13C NMR
(CDCl3, 75.5 MHz): d 25.3 (C2), 69.5 (C1), 123.6
(C2’ + C6’), 126.0 (C3’ + C5’), 147.0 (C1’), 153.1 (C4’).
Conditions for determination of the conversion by GC:
Injector 225 oC, Detector 250 oC, 80 oC (5 oC min-1) 180 oC
(0 min), tR (4a) 9.6 min and tR (4b) 11.8 min. Column
HP-1. Conditions for determination of the ee by HPLC:
0.8 mL min-1, hexane:IPA (95:5), 20 ºC, tR 11.7 min (R) and
tR 12.8 (S) min. Column AS. [α]D25 = -24.6, c 0.5, CHCl3,
for 96% ee of (S)-enantiomer.23
(S)-1-Phenylethanol, 1b
1H NMR (CDCl3, 300.13 MHz): d 1.39 (d, J 6.5 Hz, 3H,
H2), 2.03 (s, 1H, OH), 4.77 (q, J 6.5 Hz, 1H, H1), 7.25 (m,
5H, H2’ + H3’ + H4’ + H5’); 13C NMR (CDCl3, 75.5 MHz):
d 25.3 (C2 ); 70.5 (C1), 125.5 (C2’ + C6’), 127.6 (C4’), 128.6
(C3’ + C5’), 146.0 (C1’). Conditions for determination of
the conversion by HPLC: 0.8 mL min-1, Hexane:IPA
(95:5), 20 ºC, tR (1a) 5.8 min and tR (1b) 8.4 min. Column
Spherisorb. Conditions for determination of the ee by
HPLC: 0.8 mL min-1, hexane:IPA (95:5), 20 ºC, tR 10.2 (S)
and tR 15.4 (R) min. Column OB-H. [α]D25 = -47.0, c 1.1,
CHCl3, for 97% ee of (S)-enantiomer. lit.: [α]D22 = -62.8
(c 1.0, CHCl3), 98.5% ee.20
(S)-1-(2-Methoxyphenyl)ethanol, 5b
1H NMR (CDCl3, 300.13 MHz): d 1.52 (3H, d, J 6.6 Hz,
H2), 3.88 (3H, s, OCH3), 5.11 (1H, q, J 6.6 Hz, H1), 6.90
(1H, dd, J 7.5 and 1.5 Hz, H3’), 6.98 (1H, dt, J 8.5 and
1.5 Hz, H5’), 7.29 (1H, dt, J 8.5 and 1.5 Hz, H6’), 7.36 (1H,
dd, J 7.5 and 1.5 Hz, H4’); 13C NMR (CDCl3, 75.5 MHz):
d 22.8 (C2), 55.2 (OCH3), 66.3 (C1), 110.3 (C3’), 120.7
(C5’), 126.0 (C6’), 128.2 (C4’), 133.4 (C1’), 156.4 (C2’).
Conditions for determination of the conversion by HPLC:
0.8 mL min-1, hexane:IPA (95:5), 20 ºC, tR (5a) 6.3 min
and tR (5b) 7.1 min. Column Spherisorb. Conditions for
determination of the ee by HPLC: 0.8 mL min-1, hexane:IPA
(95:5), 20 ºC, tR 10.3 (S) and tR 16.8 (R) min. Column OB-H.
[α]D25 = -4.5, c 0.4, CH2Cl2, for 56% ee of (S)-enantiomer.24
(S)-1-(2-Nitrophenyl)ethanol, 2b
1H NMR (CDCl3, 300.13 MHz): d 1.55 (3H, d, J 6.3
Hz, H2), 5.40 (1H, q, J 6.3 Hz, H1), 7.41 (1H, dt, J 8.1 and
1.2 Hz, H4’), 7.63 (1H, dt, J 8.1 and 1.5 Hz, H5’), 7.82 (1H,
dd, J 8.1 and 1.2 Hz, H6’), 7.88 (1H, dd, J 8.1 and 1.5 Hz,
H3’); 13C NMR (CDCl3, 75.5 MHz): d 24.2 (C2), 65.4 (C1),
124.2 (C3’), 127.5 (C6’), 128.0 (C4’), 133.5 (C5’), 140.9
(C1’ + C2’). Conditions for determination of the conversion
by GC: Injector 225 oC, Detector 250 oC, 80 oC (5 oC min-1)
180 oC (0 min), tR (2a) 8.4 min and tR (2b) 9.2 min. Column
HP-1. Conditions for determination of the ee by HPLC:
0.8 mL min-1, hexane:IPA (97:3), 20 ºC, tR 22.1 min (R) and
(S)-1-(3-Methoxyphenyl)ethanol, 6b
1H NMR (CDCl3, 300.13 MHz): d 1.47 (3H, d, J 6.6 Hz,
H2), 3.81 (3H, s, OCH3), 4.83 (1H, q, J 6.6 Hz, H1), 6.81
(1H, dd, J 8.5 and 1.2 Hz, H6’), 6.93 (2H, m, H2’ + H4’),