V. Chhiba et al. / Journal of Molecular Catalysis B: Enzymatic 76 (2012) 68–74
71
4.22 (t, J = 0.8, 1H), 2.39 (s, 3H). 13C NMR (101 MHz, CDCl3) ı 161.48,
141.31, 132.35, 129.58, 125.79, 119.73, 62.89, 21.29 (lit [38]). HRMS
(ESI): m/z 159.0896 (M+H)+; calc. for C10H11N2: 159.0922.
2.5.2.3. 3-Amino-3-(4-methoxyphenyl)propanenitrile 3c (53% yield).
Clear oil; 1H NMR (400 MHz, CDCl3) ı 7.32–7.27 (m, 2H), 6.92–6.87
(m, 2H), 4.32–4.25 (m, 1H), 3.79 (s, 3H), 2.63 (dd, J = 5.5, 6.4, 2H), 1.74
(s, 2H). 13C NMR (101 MHz, CDCl3) ı 159.21, 134.33, 126.94, 117.96,
114.02, 55.16, 51.93, 28.42. HRMS (ESI): m/z 177.1027 (M+H)+; calc.
for C10H13N2O: 177.1028.
2.5.1.3. 3-Amino-3-(4-methoxyphenyl)acrylonitrile 3b. (36% yield).
Yellow–brown crystals, m.p. 119.4 ◦C (lit m.p. 117–118 ◦C [39]); 1
H
NMR (400 MHz, CDCl3) ı 7.47–7.42 (m, 2H), 6.95–6.90 (m, 2H), 4.98
(s, 2H), 4.17 (s, 1H), 3.83 (s, 3H). 13C NMR (101 MHz, CDCl3) ı 161.60,
161.17, 133.87, 127.36, 119.94, 114.12, 62.07, 55.34 (lit [38,40]).
HRMS (ESI): m/z 175.0880 (M+H)+; calc. for C10H11N2O: 175.0871.
2.5.2.4. 3-Amino-3-(4-chlorophenyl)propanenitrile 4c (52% yield).
Clear oil; 1H NMR (400 MHz, CDCl3) ı 7.40–7.30 (m, 4H), 4.37–4.29
(m, 1H), 2.73–2.58 (m, 2H), 1.99 (s, 2H). 13C NMR (101 MHz, CDCl3)
ı 140.45, 133.92, 128.98, 127.36, 117.56, 51.94, 28.23. HRMS (ESI):
m/z 181.0522 (M+H)+; calc. for C9H10N2Cl: 181.0533.
Beige powder, m.p. 124.8 ◦C (lit m.p. 140–144 ◦C [40]); 1H NMR
(400 MHz, CDCl3) ı 7.48–7.39 (m, 5H), 4.89 (s, 2H), 4.24 (t, J = 0.9,
1H). 13C NMR (101 MHz, CDCl3) ı 160.26, 136.97, 133.70, 129.22,
127.33, 119.13, 64.27 (lit [38]). HRMS (ESI): m/z 179.0357 (M+H)+;
calc. for C9H8N2Cl: 179.0376.
2.5.2.5. 3-Amino-3-(4-bromophenyl)propanenitrile 5c. (26% yield).
Yellow oil; 1H NMR (400 MHz, CDCl3) ı 7.46 (d, J = 8.5, 2H), 7.25
(d, J = 8.5, 2H), 4.25 (t, J = 6.3, 1H), 2.70–2.53 (m, 2H), 1.80 (s,
2H). 13C NMR (101 MHz, CDCl3) ı 141.07, 131.37, 127.44, 121.33,
117.48, 51.48, 27.74. HRMS (ESI): m/z 225.0027 (M+H)+; calc. for
C9H10N2Br: 225.0027.
2.5.1.5. 3-Amino-3-(4-bromophenyl)acrylonitrile 5b (42% yield).
Yellow powder, m.p. 135 ◦C (lit m.p.147–148 ◦C [37]); 1H NMR
(400 MHz, CDCl3) ı 7.60–7.54 (m, 2H), 7.41–7.35 (m, 2H), 4.90 (s,
2H), 4.25 (d, J = 0.8, 1H). 13C NMR (101 MHz, CDCl3) ı 160.35, 134.17,
132.17, 127.54, 125.23, 119.13, 64.21 (lit [38]). HRMS (ESI): m/z
222.9867 (M+H)+; calc. for C9H8N2Br: 222.9871.
2.5.2.6. 3-Amino-3-(3-bromophenyl)propanenitrile 6c (40% yield).
Yellow oil; 1H NMR (400 MHz, CDCl3) ı 7.55 (t, J = 1.8, 1H), 7.45 (ddd,
J = 1.2, 1.9, 7.8, 1H), 7.35–7.29 (m, 1H), 7.29–7.21 (m, 1H), 4.31 (dd,
J = 5.7, 7.1, 1H), 2.67 (m, 2H), 1.85 (s, 2H). 13C NMR (101 MHz, CDCl3)
ı 144.45, 131.26, 130.40, 129.03, 124.65, 122.81, 117.50, 52.05,
28.20. HRMS (ESI): m/z 225.0007 (M+H)+; calc. for C9H10N2Br:
225.0027.
2.5.1.6. 3-Amino-3-(3-bromophenyl)acrylonitrile 6b (33% yield).
Yellow powder; 1H NMR (400 MHz, CDCl3) ı 7.65 (t, J = 1.8, 1H), 7.59
(ddd, J = 1.0, 2.0, 8.0, 1H), 7.44 (ddd, J = 1.1, 1.8, 7.8, 1H), 7.30 (t, J = 7.9,
1H), 5.05 (s, 2H), 4.22 (t, J = 0.9, 1H). 13C NMR (101 MHz, CDCl3)
ı 159.99, 137.24, 133.74, 130.44, 129.07, 124.66, 122.91, 119.02,
64.30. HRMS (ESI): m/z 222.9822 (M+H)+; calc. for C9H8N2Br:
222.9871.
2.5.3. General method for biotransformation of ˇ-aminonitriles
to ˇ-amino-amides (compounds 1d–6d)
3-Amino-3-phenylpropanenitrile (100 mg) was incubated with
resting cells of R. rhodochrous ATCC BAA-870 in a 100 mM Tris
buffer, pH 9.0. Incubation was at 5 ◦C or 30 ◦C with agitation and
reaction sampling/termination being done at varying time periods
(0 min – 25 h).
2.5.2. General method for preparation of
3-amino-3-phenylpropanenitriles (compounds 1c–6c)
exemplified by 1c
3-Amino-3-phenylacrylonitrile (1b) (3.00 g, 20.8 mmol) was
dissolved in absolute ethanol (50 ml). Sodium cyanoborohydride
(1.44 g, 22.9 mmol) was added, followed by bromocresol green (1
drop of a 0.5% solution in ethanol). Concentrated HCl (32%) was
added dropwise until a permanent yellow colour was obtained.
The reaction was stirred at room temperature for 3 h. Water was
added, followed by concentrated aqueous ammonia (25%) to about
pH 11. The aqueous layer was extracted with diethyl ether (×3) and
the combined organic layers were washed with brine, dried over
MgSO4 and the solvent removed in vacuo. The resulting brown oil
was purified by column chromatography (elution ethyl acetate) to
yield 3-amino-3-phenylpropanenitrile (1.79 g, 59%) as a colourless
oil.
2.5.3.1. 3-Amino-3-phenylpropanamide 1d (23% yield). White pow-
der; m.p. 110.1 ◦C; 1H NMR (400 MHz, CDCl3) ı 7.37–7.30 (m, 5H),
6.94 (s, 1H), 5.54 (s, 1H), 4.37 (t, J = 6.7, 1H), 2.59–2.54 (m, 2H), 2.04
(s, 2H). 13C NMR (101 MHz, CDCl3) ı 174.38, 143.53, 128.65, 127.52,
125.97, 52.38, 43.90. HRMS (ESI): m/z 165.1042 (M+H)+; calc. for
C9H13N2O: 165.1028.
2.5.3.2. 3-Amino-3-p-tolylpropanamide 2d (22% yield). Yellow
powder; 1H NMR (400 MHz, CDCl3) ı 7.22 (d, J = 8.1, 2H), 7.18–7.12
(m, 2H), 7.02 (s, 1H), 5.73 (s, 1H), 4.32 (t, J = 6.7, 1H), 2.53 (d, J = 6.5,
2H), 2.34 (s, 3H), 1.96 (s, 2H). 13C NMR (101 MHz, CDCl3) ı 174.02,
141.98, 137.07, 129.38, 125.68, 52.54, 44.82, 21.02. HRMS (ESI):
m/z 179.1287 (M+H)+; calc. for C10H14N2O2Na: 179.1284.
2.5.2.1. 3-Amino-3-phenylpropanenitrile 1c (59% yield). Clear oil; 1H
NMR (400 MHz, CDCl3) ı 7.35 (m, 4H), 7.31–7.25 (m, 1H), 4.27 (dd,
J = 5.8, 7.1, 1H), 2.68–2.55 (m, 2H), 1.73 (s, 2H). 13C NMR (101 MHz,
CDCl3) ı 142.17, 128.55, 127.85, 125.65, 117.80, 52.25, 28.06. 13C
NMR (101 MHz, CDCl3) ı 143.92, 129.89, 129.13, 127.46, 119.31,
53.82, 28.29. HRMS (ESI): m/z 147.0909 (M+H)+; calc. for C9H11N2:
147.0922.
2.5.3.3. 3-Amino-3-(4-methoxyphenyl)propanamide 3d (16% yield).
White powder; 1H NMR (400 MHz, CD3OD) ı 7.63 (br s, 1H), 7.53
(br s, 1H), 7.35–7.27 (m, 2H), 6.92–6.85 (m, 2H), 4.55–4.49 (m, 1H),
3.71 (s, 3H), 2.83 (qd, J = 7.2, 15.8, 2H). 13C NMR (101 MHz, CDCl3) ı
174.21, 158.89, 127.23, 127.20, 114.02, 55.21, 51.88, 43.85. HRMS
(ESI): m/z 217.0926 (M+H)+; calc. for C10H14N2O2Na: 217.0953.
2.5.2.2. 3-Amino-3-p-tolylpropanenitrile 2c (53% yield). Clear oil; 1H
NMR (400 MHz, CDCl3) ı 7.29–7.24 (m, 2H), 7.21–7.15 (m, 2H), 4.30
2.5.3.4. 3-Amino-3-(4-bromophenyl)propanamide 5d (28% yield).
Yellow powder; 1H NMR (400 MHz, CDCl3) ı 7.48 (d, J = 8.4, 2H),
7.25 (d, J = 8.4, 2H), 4.43–4.35 (m, 1H), 2.75–2.39 (m, 2H), 1.26 (s,
4H). 13C NMR (101 MHz, CDCl3) ı 173.83, 141.80, 131.72, 127.92,
121.41, 51.85, 43.24. HRMS (ESI): m/z 243.0150 (M+H)+; calc. for
C9H12N2OBr: 243.0133.
(dd, J = 5.8, 7.1, 1H), 2.71–2.58 (m, 1H), 2.35 (s, 3H), 1.73 (s, 2H). 13
C
NMR (101 MHz, CDCl3) ı 139.37, 137.93, 129.48, 125.72, 117.96,
52.33, 28.45, 21.03. HRMS (ESI): m/z 161.1083 (M+H)+; calc. for
C10H13N2: 161.1079.