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N. Bala et al. / Journal of Molecular Catalysis B: Enzymatic 63 (2010) 128–134
(R)-3-(4ꢀ-Nitrophenoxy)propane-1,2-diol (2h): Yield 6%; yel-
CH), 3.09–3.16 (m, 2H, CH2), 7.16–7.23 (m, 3H, ArH), 7.38–7.40
(m, 2H, ArH). 13C NMR (100.61 MHz, CDCl3): 31.6, 41.9, 45.7, 121.5,
123.7, 125.3, 130.4; enantiomeric excess 23%; determined by HPLC
(Daicel Chiralpak OD-H, hexane/i-PrOH 95:5); flow rate 1 mL/min;
ꢀ = 218 nm; tR (R) 7.54 min, tR (S) 7.24 min.
low oil; 1H NMR (300 MHz, CDCl3 + DMSO): ı 3.64–3.76 (m,
1H, CH2), 4.03–4.19 (m, 3H, CH and CH2), 4.52–4.62 (bs, 2H,
OH), 7.00–7.09 (m, 2H, ArH), 8.14–8.20 (m, 2H, ArH); 13C NMR
(75.45 MHz, CDCl3 + d6-DMSO): 62.8, 69.5, 69.6, 114.2, 125.3, 140.9,
163.6; enantiomeric excess 20%; determined by HPLC (Daicel
Chiralpak AD-H, hexane/i-PrOH 90:10); flow rate 1.0 mL/min;
ꢀ = 218 nm; tR (R) 31.32 min, tR (S) 35.78 min.
(R)-3-(Phenylthio)propane-1,2-diol (2n): Yield 70%; white
solid; 1H NMR (500 MHz, CD3OD): ı 3.00 (dd, J = 6.86 and 13.5 Hz,
1H, CH2), 3.10 (dd, J = 5.98 and 13.5 Hz, 1H, CH2), 3.59 (dd, J = 5.89
and 11.3 Hz, 1H, CH2), 3.66 (dd, J = 4.14 and 11.3 Hz, 1H, CH2),
3.76–3.78 (m, 1H, CH2), 7.15–7.18 (m, 1H, ArH), 7.25–7.28 (m, 2H,
ArH), 7.36–7.38 (m, 2H, ArH); 13C NMR (125.75 MHz, CD3OD): 37.3,
65.4, 71.2, 126.6, 129.4, 129.7, 136.8; enantiomeric excess 27%;
determined by HPLC (Daicel Chiralpak OD-H, hexane/i-PrOH 95:5);
flow rate 1 mL/min; ꢀ = 218 nm; tR (R) 34.1 min, tR (S) 31.3 min.
(S)-1,2-Epoxy-3-(benzyloxy)propane (1o): Yield 50%; colour-
less oil; 1H NMR (300 MHz, CDCl3): ı 2.57 (dd, J = 3.0 and 5.0 Hz,
1H, CH2), 2.75 (dd, 1H, J = 4.2 and 5.0 Hz, CH2), 3.10–3.15 (m, 1H,
CH), 3.41 (dd, J = 5.7 and 11.4 Hz, 1H, CH2), 3.71 (dd, J = 3.0 and
11.4 Hz, 1H, CH2), 4.53 (d, J = 12.0 Hz, 1H, CH2), 4.59 (d, J = 12.0 Hz,
1H, CH2), 7.23–7.32 (m, 5H, ArH); 13C NMR (75.45 MHz, CDCl3):
44.0, 50.7, 70.7, 73.2, 127.6, 128.3, 137.9; enantiomeric excess 30%;
determined by HPLC (Daicel Chiralpak OD-H, hexane/i-PrOH 93:7);
flow rate 0.5 mL/min; ꢀ = 218 nm; tR (S), 17.93 min tR (R) 19.64.
(R)-3-(Benzyloxy)propane-1,2-diol (2o): (RS)-3-(Benzyloxy)
propane-1,2-diol [11] (2o): Yield 50%; colourless oil; 1H NMR
(300 MHz, CDCl3): ı 2.02–2.56 (bs, 2H, OH), 3.46–3.70 (m, 4H, CH2),
(S)-1,2-Epoxy-3-(3ꢀ-chlorophenoxy)propane (1j): Yield 33%;
colourless oil; 1H NMR (300 MHz, CDCl3): ı 2.70 (dd, J = 2.7 and
5.0 Hz, 1H, CH2), 2.86 (t, J = 4.5 Hz, 1H, CH2), 3.26–3.31 (m, 1H, CH),
3.92 (dd, J = 5.4 and 11.0 Hz, 1H, CH2), 4.16 (dd, J = 3.3 and 11.1 Hz,
1H, CH2), 6.75–6.79 (m, 1H, ArH), 6.87–6.94 (m, 2H, ArH), 7.14–7.25
(m, 2H, ArH); 13C NMR (75.45 MHz, CDCl3): 44.4, 49.7, 69.0, 113.1,
115.1, 121.4, 130.2, 135.0, 159.2; enantiomeric excess >99%; deter-
mined by HPLC (Daicel Chiralpak OD-H, hexane/i-PrOH 95:5); flow
rate 1 mL/min; ꢀ = 218 nm; tR (R) 8.71 min, tR (S) 9.14 min.
(R)-3-(3ꢀ-Chlorolphenoxy)propane-1,2-diol (2j): Yield 67%;
white solid; 1H NMR (300 MHz, CDCl3): ı 3.03 (bs, 2H, OH), 2.92
(bs, 1H, OH), 3.72 (dd, J = 6.0 and 11.5, 1H, CH2), 3.82 (dd, J = 3.0 and
11.4 Hz, 1H, CH2), 3.98–4.03 (m, 2H, CH2), 4.06–4.13 (m, 1H, CH)
6.76–6.80 (m, 1H, ArH), 6.89–6.96 (m, 2H, ArH), 7.15–7.20 (m, 1H,
ArH); 13C NMR (75.45 MHz, CDCl3): 63.5, 69.2, 70.3, 112.9, 115.0,
121.5, 130.3, 134.9, 159.1; enantiomeric excess 68%; determined
by HPLC (Daicel Chiralpak OD-H, hexane/i-PrOH 95:5); flow rate
1 mL/min; ꢀ = 218 nm; tR (R) 29.84 min, tR (S) 38.88 min.
(S)-1,2-Epoxy-3-(2-chlorophenoxy)propane (1k): Yield 40%;
colourless oil; 1H NMR (300 MHz, CDCl3): ı 2.78 (dd, J = 2.7 and
5.25 Hz, 1H, CH2), 2.88 (dd, J = 4.2 and 4.95 Hz, 1H, CH2), 3.32–3.37
(m, 1H, CH), 4.06 (dd, J = 5.1 and 11.1 Hz, 1H, CH2), 4.22 (dd, J = 3.6
and 11.1 Hz, 1H, CH2), 6.86–6.94 (m, 2H, ArH), 7.13–7.19 (m, 1H,
ArH), 7.31–7.35 (m, 1H, ArH); 13C NMR (125.75 MHz, CDCl3): 44.5,
50.0, 69.7, 114.1, 122.2, 123.1, 127.7, 130.3, 154.0; enantiomeric
excess 93%; determined by HPLC (Daicel Chiralpak OD-H, hexane/i-
PrOH 95:5); flow rate 1 mL/min; ꢀ = 218 nm; tR (R) 10.93 min, tR (S)
11.99 min.
3.82–3.88 (m, 1H, CH2), 4.53 (s, 2H, CH), 7.25–7.35 (m, 5H, ArH); 13
C
NMR (125.75 MHz, CDCl3): 64.0, 70.7, 71.7, 73.5, 127.8, 127.9, 128.4,
128.5, 137.6; enantiomeric excess 40%; determined by HPLC (Dai-
cel Chiralpak OD-H, hexane/i-PrOH 93:7); flow rate 0.5 mL/min;
ꢀ = 218 nm; tR (R) 43.29 min, tR (S) 55.0 min.
3. Results and discussions
The different isolates (80) were screened for epoxide hydrolase
activity using phenyl glycidyl ether (1a) as substrate following the
protocol described in Section 2.3. Five isolates designated as MO-
10, AO5, AO6, WH-15 and HA-13 were capable of carrying out the
hydrolysis of 1a. The isolates AO6 and AO5 afforded the conversion
of 30% and 25%, respectively to the corresponding racemic diol.
The isolates MO-10, WH-15 and HA-13 resulted in enantioselec-
tive kinetic resolution of phenyl glycidyl ether yielding (S)-phenyl
glycidyl ether (1a) with an ee of 70%, 20% and >99%, respectively,
and (R)-(phenoxy)propan-1,2-diol (2a) with an ee of 45%, 8% and
68%, respectively. The isolate HA-13 was chosen for further stud-
ies as it supported the highest enantioselectivity of (S)-phenyl
glycidyl ether and (R)-(phenoxy)propan-1,2-diol out of these five
isolates. This isolate was deposited in MTCC, IMTECH, Chandigarh
(India) under the accession number 10234 and was identified as B.
alcalophilus.
The comparison of these results with the literature reports the
untransformed phenyl glycidyl ether was assigned (S)-absolute
to obtain these results since the (S)-enantiomer of phenyl glycidyl
ether (1a) is useful for synthesis of bioactive -blocker [18] and
(R)-(phenoxy)propan-1,2-diol (2a) is an important intermediate in
synthesis of various bioactive molecules [22].
(R)-3-(2ꢀ-Chlorophenoxy)propane-1,2-diol (2k): Yield 60%;
white solid; 1H NMR (500 MHz, CDCl3): ı 3.18–3.19 (bs, 1H, OH),
3.63 (bs, 1H, OH), 3.77–3.86 (m, 2H, CH2), 4.05–4.13 (m, 3H, CH
and CH2), 3.97 (m, 2H, CH2), 4.03–4.10 (m, 1H, CH), 6.88–6.91
(m, 2H, ArH), 7.17–7.20 (m, 1H, ArH), 7.32–7.34 (m, 1H, ArH). 13C
NMR (125.75 MHz, CDCl3): 63.9, 67.9, 70.5, 113.6, 121.7, 122.6,
127.6, 129.8, 153.5; enantiomeric excess 78%; determined by HPLC
(Daicel Chiralpak OD-H, hexane/i-PrOH 98:2); flow rate 1 mL/min;
ꢀ = 218 nm; tR (R) 35.51 min tR (S) 38.49 min.
(S)-1,2-Epoxy-3-(4ꢀ-bromophenoxy)propane (1m): Yield 33%;
white solid; m.p. 55–56 ◦C; 1H NMR (300 MHz, CDCl3): ı 2.64–2.68
(m, 1H, CH2), 2.80–2.84 (m, 1H, CH2), 3.23–3.27 (m, 1H, CH),
4.09–4.15 (m, 1H, CH2), 4.09–4.15 (m, 1H, CH2), 6.72–6.76 (m, 2H,
ArH), 7.28–7.33 (m, 1H, ArH), 7.31–7.35 (m, 1H, ArH). 13C NMR
(100.61 MHz, CDCl3): 44.5, 49.9, 69.3, 113.6, 116.7, 132.3, 157.8;
enantiomeric excess >99%; determined by HPLC (Daicel Chiralpak
AD-H, hexane/EtOH 99.5:0.5); flow rate 1 mL/min; ꢀ = 228 nm; tR
(R) 21.9 min, tR (S) 20.3 min.
(R)-3-(4ꢀ-Bromophenoxy)propane-1,2-diol (2m): Yield 67%;
white solid; 1H NMR (300 MHz, CDCl3): ı 1.28 (bs, 1H, OH), 2.89
(bs, 1H, OH), 3.69 (dd, J = 5.1 and 11.3 Hz, 1H, CH2), 3.80 (dd,
J = 4.8 and 11.4 Hz, 1H, CH2), 3.97 (m, 2H, CH2), 4.03–4.10 (m,
1H, CH), 6.74–6.83 (m, 2H, ArH), 7.17–7.38 (m, 2H, ArH); 13C
NMR (75.45 MHz, CDCl3): 63.5, 69.4, 70.3, 113.5, 116.3, 130.4,
132.4, 157.5; enantiomeric excess 72%; determined by HPLC (Dai-
cel Chiralpak AD-H, hexane/i-PrOH 90:10); flow rate 1 mL/min,
ꢀ = 228 nm; tR (R) 13.4 min, tR (S) 14.8 min.
In order to study the scope and limitation of this biotransfor-
mation process different substituted aryl glycidyl ether derivatives
were subjected to hydrolytic kinetic resolution by the growing cells
of B. alcalophilus MTCC10234 (Fig. 1). In all the cases the enzyme
preferentially hydrolyzes (R)-enantiomer of racemic phenyl gly-
cidyl ether, resulting in the hydrolytic kinetic resolution of the
substrates. The untransformed aryl glycidyl ether derivatives were
obtained in high enantioselectivity (up to >99%) and the diol deriva-
(S)-1,2-Epoxy-3-(phenylthio)propane (1n): Yield 30%; colour-
less oil; 1H NMR (300 MHz, CDCl3): ı 2.47 (dd, J = 2.4 and 4.9 Hz,
1H, CH2), 2.72 (dd, J = 3.9 and 4.8 Hz, 1H, CH2), 2.87–2.95 (m, 1H,