Eco-friendly synthesis of α-aminonitriles from ketones in PEG-400 medium using potassium Hexacyanoferrate(II) as cyanide source

Article abstract of DOI:10.1016/j.jorganchem.2012.02.005

An efficient method for the synthesis of α-aminonitriles via one-pot three-component condensation of ketones, amines and potassium hexacyanoferrate(II) using benzoyl chloride as a promoter and PEG-400 as a reaction medium was described. This protocol has

Full text of DOI:10.1016/j.jorganchem.2012.02.005

Journal of Organometallic Chemistry 705 (2012) 70e74
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Eco-friendly synthesis of
a-aminonitriles from ketones in PEG-400 medium
using potassium Hexacyanoferrate(II) as cyanide source
,
,
*
Xiaochun Hu a b, Yuanhong Ma a, Zheng Li a
a College of Chemistry and Chemical Engineering, Northwest Normal University, East Anning Road 967, Lanzhou, Gansu, 730070, PR China
b Editorial Department of The University Journal, Northwest Normal University, Lanzhou, Gansu, 730070, China
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient method for the synthesis of a-aminonitriles via one-pot three-component condensation of
Received 24 December 2011
Received in revised form
26 January 2012
ketones, amines and potassium hexacyanoferrate(II) using benzoyl chloride as a promoter and PEG-400
as a reaction medium was described. This protocol has the features of use of eco-friendly cyanide source,
green reaction medium, high yield, and simple work-up procedure.
Accepted 1 February 2012
Ó 2012 Elsevier B.V. All rights reserved.
Keywords:
a
-Aminonitrile
Multicomponent reaction
PEG-400
Potassium hexacyanoferrate(II)
Strecker reaction
1. Introduction
aldehydes. Therefore, there is a need to explore eco-friendly
cyanide source and green reaction medium for the Strecker reac-
The Strecker reaction provides one of the most important and
straight forward method for the synthesis of -aminonitriles [1e4],
which are significantly important intermediates for the synthesis of
tion and synthesis of a-aminonitriles from ketones.
a
Polyethylene glycol (PEG) is an inexpensive, thermally stable,
non-volatile, recoverable, biological compatible, non-toxic and
easily degradable substance. Recently it has received considerable
attention in synthetic organic chemistry as green organic solvents
[41e43]. Meanwhile, potassium hexacyanoferrate(II), K4[Fe(CN)6],
is non-toxic and is even used in the food industry for metal
precipitation. In addition, it has been described as an anti-
agglutinating auxiliary for table salt (NaCl). K4[Fe(CN)6] is a by-
product of coal chemical industry and commercially available on
a ton scale, and is even cheaper than KCN. Recently, K4[Fe(CN)6] has
been used as a cyanide source in the synthesis of benzonitriles
[44e58] and aroyl cyanides [59]. Our current research focused on
the cyanation of unsaturated compounds by nucleophilic additional
reactions using K4[Fe(CN)6] as an eco-friendly cyanide source
[60e63]. As a part of this work, in this study, we report an efficient
a wide variety of amino acids, amides, diamines and nitrogen-
containing heterocycles [5e9]. In general,
a-aminonitriles are
synthesized by the reactions of aldehydes/ketones with amines in
the presence of a cyanide source such as HCN [10,11], KCN [12],
TMSCN [13,14], (EtO)2P(O)CN [15], Et2AlCN [16], Bu3SnCN [17,18],
MeCOCN [19], acetone cyanohydrin [20,21] and ethyl cyanoformate
[22,23]. However, these cyanide sources are often hazardous and
toxic, and involve harsh reaction conditions. Recently, numerous
methods have also been developed for the synthesis of a-amino-
nitriles from aldehyde/ketone, amine and trimethylsilyl cyanide
catalyzed by Cu(OTf)2 [24], BiCl3 [25], NiCl2 [26], InI3 [27e29], RuCl3
[30,31], Sc(OTf)3 [32], La(NO3)3.6H2O or GdCl3.6H2O [33], I2 [34,35],
H4SiW12O40/Al2O3 [36], K2PdCl4 [37], Al-MCM-41 [38], Brønsted
acid [39] and metal complexes [40] in conventional organic
solvents. However, trimethylsilyl cyanide is sensitive to moisture
and can easily liberate toxic hydrogen cyanide. Meanwhile many of
these reported methods involve the use of expensive reagents, toxic
organic solvents, tedious work-up procedure and longer reaction
times. Furthermore, many of these protocols are only limited to
method for the synthesis of
a-aminonitriles from ketones using
K4[Fe(CN)6] as an efficient nucleophilic addition reagent and an eco-
friendly cyanide source, and PEG-400 as a green reaction medium.
2. Results and discussion
Generally, the synthesis of
easier to afford the products in higher yield. In contrast, the
a-aminonitriles from aldehydes is
* Corresponding author. Tel.: þ869317971533; fax: þ869317971989.
E-mail address: lizheng@nwnu.edu.cn (Z. Li).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2012.02.005

X. Hu et al. / Journal of Organometallic Chemistry 705 (2012) 70e74
71
Table 1
Synthesis of
synthesis of a-aminonitriles from ketones is more difficult because
of steric hindrance effect.
a
-aminonitriles from ketones using different promoters.a
Promoter
Yield (%)b
In order to explore the synthetic method of
a-aminonitriles
Entry
from ketones, and using K4[Fe(CN)6] as an environmentally friendly
cyanide source, the initial synthesis of -aminonitrile was selected
acetophenone, aniline and K4[Fe(CN)6] as model substrates
(Scheme 1).
O
a
1
2
0
0
Cl
O
2.1. The effect of promoters on the reaction
Cl
Cl
The three-component reaction was ever attempted under
different conditions using Lewis acids, Lewis bases or metal
complexes as catalysts. Unfortunately, no any products were
observed because of the inactivity of K4[Fe(CN)6]. However, in the
later research, it was found that some acyl chlorides could effi-
ciently promote the three-component reaction of acetophenone,
aniline and K4[Fe(CN)6] (Table 1). Among the selected acyl chlo-
rides, acetyl chloride and oxalyl chloride were not valid for the
reaction because of their volatility and instability (Table 1, entries
1e2). Phenylsulfonyl chloride and furoyl chloride could only
O
O
3
4
65
62
Cl
O
O
S
Cl
promote the reaction to give the corresponding
middle yield (Table 1, entries 3e4). However, many aroyl chlorides
could promote the reaction to afford the desired -aminonitrile
a-aminonitrile in
O
a
O
in high yield (Table 1, entries 5e10). Especially, benzoyl chloride
acted as the best promoter (Table 1, entry 5). In addition, it was
also found that for 1 mol of acetophenone and aniline, only 0.2
equivalent of K4[Fe(CN)6] was required, which indicated that all
CNꢀ in K4[Fe(CN)6] could be readily utilized in this reaction.
5
6
82
78
Cl
O
Cl
Cl
2.2. The effect of solvents on the reaction
Cl
The further research showed that solvents also played a crucial
role in the one-pot three-component reaction of acetophenone,
aniline and K4[Fe(CN)6] using benzoyl chloride as a promoter
O
7
8
76
74
(Table 2). It was found that
a-aminonitrile was obtained in
moderate yield in THF, MeCN and EtOH. However, when PEG-400
was chosen to be a reaction medium, the desired product was ob-
tained in highest yield within shortest time (Table 2, entries 4). In
addition, PEG-200 and PEG-600 could also be used as a good
reaction medium in a similar manner to PEG-400. However, PEGs
having more than 800 of average molecular weight were not suit-
able to the reaction medium because of their solid state property at
room temperature.
CH3
O
Cl
CH3
O
2.3. General results at optimal conditions
9
73
71
Cl
Cl
C2H5
Based on above promising findings, a series of one-pot three-
component reactions of ketones, amines and K4[Fe(CN)6] were
investigated in PEG-400 using benzoyl chloride as a promoter
(Scheme 2, Table 3). Aromatic ketones bearing both electron-
withdrawing and electron-donating groups could participate in
O
10
reactions to afford the desired
a-aminonitriles in high yield.
CH3O
However, aromatic ketones bearing electron-withdrawing groups
worked better than ketones bearing electron-donating groups.
Aliphatic ketones, for example, cyclopentanone and cyclohexa-
none, were also suitable to the three-component reactions
although the reaction rate was slightly slower than aromatic
ketones. Meanwhile most aromatic amines were effective to the
a
Reaction condition: acetophenone (2 mmol), aniline (2 mmol), promoter
(2 mmol) and K4[Fe(CN)6] (0.4 mmol) in 5 mL of PEG-400.
b
Isolated yield.
one-pot three-component reactions except for the amines bearing
strong electron-withdrawing groups on the aryl ring, such as nitro,
CN
O
which could not give
a-aminonitriles because the nucleophilic
NH2
property of amines were weakened by nitro group. The promoter,
benzoyl chloride, was transformed into benzoic acid in the reac-
tions, which could be easily recovered from the reaction system and
further reused after regeneration.
K4[Fe(CN)6]
+
+
N
H
Scheme 1. Synthesis of 2-phenyl-2-(phenylamino)propanenitrile.

72
X. Hu et al. / Journal of Organometallic Chemistry 705 (2012) 70e74
Table 2
Synthesis of a
-aminonitriles from ketones in different solvents.a
Table 3
Entry
Solvent
Reaction time (h)
Yield (%)b
Synthesis of a-aminonitriles from ketones in PEG-400 medium using K4[Fe(CN)6] as
cyanide source.a
1
2
3
4
THF
MeCN
EtOH
10
10
10
6
56
60
76
82
Entry
Ketone
Amine
Reaction Yield (%)b
time (h)
PEG-400
a
Reaction condition: acetophenone (2 mmol), aniline (2 mmol), benzoyl chloride
(2 mmol) and K4[Fe(CN)6] (0.4 mmol) in 5 mL of solvent.
O
NH2
1
2
3
4
5
6
5
5
6
7
7
82
84
83
78
76
80
b
Isolated yield.
2.4. Mechanism for the synthesis of
a-aminonitriles from ketones
O
O
O
O
NH2
CH3
A plausible mechanism for the synthesis of
a
-aminonitriles from
ketones using K4[Fe(CN)6] as cyanide source, according to Hunig’s
review [64], is shown in Scheme 3. K4[Fe(CN)6] first reacts with
benzoyl chloride to form benzoyl cyanide. Then benzoyl cyanide is
attacked by water to produce hydrogen cyanide in situ. Finally,
nucleophilic addition of cyanide ion to the imines, which is formed
NH2
CH3
from condensation of ketones and amines, yield a-aminonitriles.
NH2
3. Conclusion
In summary, an efficient and eco-friendly method for the
synthesis of -aminonitriles through one-pot three-component
a
NH2
condensation of ketones, amines and K4[Fe(CN)6] using benzoyl
chloride as a promoter and PEG-400 as a green medium was
developed. The significant features of this protocol are the use of
non-toxic, inexpensive K4[Fe(CN)6] as cyanide source to replace the
traditional strong toxic and volatile cyanating agents, the use of
PEG-400 as green solvent, the no use of metal catalysts, the high
yield, and the simplicity of reaction and work-up procedure.
Cl
O
NH2
6
Br
4. Experimental
O
NH2
NH2
7
6
5
5
75
86
88
4.1. General considerations
CH3O
IR spectra were recorded using KBr pellets on an Alpha Centauri
FTIR spectrophotometer. 1H NMR and 13C NMR spectra on
a Mercury-400BB instrument using CDCl3 as solvent and Me4Si as
internal standard. Elemental analyses were performed on a Vario El
Elemental Analysis instrument. Melting points were observed in an
electrothermal melting point apparatus. Potassium hex-
acyanoferrate(II) dried at 80 ꢁC under vacuum for 24 h and finely
powdered prior to use.
O
8
O2N
O
NH2
9
4.2. The general procedure for the synthesis of
ketones
a-aminonitriles from
CH3
Cl
The mixture of K4[Fe(CN)6] (0.4 mmol) and benzoyl chloride
(2 mmol) was heated at 160 ꢁC for 2 h, then the reaction system was
cooled to 80 ꢁC, ketone (2 mmol) and aniline (2 mmol) in 5 mL of
PEG-400 were added. The resulting mixture was further stirred at
80 ꢁC for appropriate time indicated in Table 3. After completion of
the reaction monitored by TLC, water (20 mL) was added, and the
mixture was extracted with diethyl ether (3 ꢂ 10 mL). Then the
NH2
10
11
8
8
78
80
O
O
NH2
CH3
NH2
CN
12
8
77
O
R1
R2
COCl
R3
+
O
R3NH2
K4[Fe(CN)6]
+
R1
N
H
a
Reaction condition: ketone (2 mmol), amine (2 mmol), benzoyl chloride
(2 mmol) and K4[Fe(CN)6] (0.4 mmol) in 5 mL of PEG-400.
PEG-400
R2
b
Isolated yield.
Scheme 2. Synthesis of
a-aminonitriles from ketones using K4[Fe(CN)6] as cyanide
source.

X. Hu et al. / Journal of Organometallic Chemistry 705 (2012) 70e74
73
119.4, 120.1, 120.7, 124.2, 124.8, 125.4, 125.8, 128.6, 129.0, 129.2,
134.2, 137.9, 139.4. Anal. Calcd. for C19H16N2: C, 83.79; H, 5.92; N,
10.29. Found: C, 83.66; H, 5.91; N, 10.33.
KCl, FeCl2
H2O
O
H
Ph
CN
O
K4[Fe(CN)6]
Ph
4.3.5. 2-(4-Chlorophenylamino)-2-phenylpropanenitrile (Table 3,
entry 5)
CN
Ph
O
White solid, mp 137e138 ꢁC. IR (KBr): 3379, 2989, 2233, 1601,
OH
1516, 1318, 1257, 807, 699 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d
1.94 (s,
3H), 4.29 (s, 1H), 6.46e6.48 (m, 2H), 7.06e7.08 (m, 2H), 7.26e7.38
(m, 3H), 7.38e7.61 (m, 2H). 13C NMR (CDCl3, 100 MHz):
33.3,
Cl
O
d
57.2, 116.9, 120.4, 124.8, 125.1, 128.8, 129.0, 129.3, 139.4, 142.0. Anal.
Calcd. for C15H13ClN2: C, 70.18; H, 5.10; N, 10.91. Found: C, 70.09; H,
5.11; N, 10.95.
H
C
CN
N
Ph
OH
CN
R1
R2
4.3.6. 2-(Phenylamino)-2-(4-bromophenyl)propanenitrile (Table 3,
entry 6)
R3
O
R1
R2
N
H
R1
R2
White solid, mp 156e157 ꢁC. IR (KBr): 3380, 2936, 2230, 1603,
R3
1514, 1316, 1261, 751, 694 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d
1.91 (s,
3H), 4.27 (s, 1H), 6.50e6.53 (m, 2H), 6.80e6.85 (m, 1H), 7.10e7.26
(m, 2H), 7.49e7.55 (m, 4H). 13C NMR (CDCl3, 100 MHz):
33.3,
R3 NH2
H2O
d
Scheme 3. Proposed mechanism for synthesis of a-aminonitriles from ketones using
56.7, 115.7, 120.2, 122.6, 126.7, 129.1, 132.4, 139.0, 143.1. Anal. Calcd.
for C15H13BrN2: C, 59.82; H, 4.35; N, 9.30. Found: C, 59.88; H, 4.34;
N, 9.35.
K4[Fe(CN)6] as cyanide source.
combined organic layers were dried with anhydrous sodium sulfate
and the solvent was removed by evaporation. The residue was
subjected to column chromatography to give pure product.
4.3.7. 2-(Phenylamino)-2-(4-methoxyphenyl)propanenitrile
(Table 3, entry 7)
White solid, mp 94e95 ꢁC. IR (KBr): 3385, 2932, 2230, 1605,
1514, 1317, 1256, 832, 693 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d 1.93 (s,
4.3. The analytical data for the products
3H), 3.81 (s, 3H), 4.24 (s, 1H), 6.54e6.56 (d, 2H, J ¼ 8.8 Hz),
6.78e6.82 (m, 1H), 6.90e6.92 (m, 2H), 7.10e7.26 (m, 2H), 7.52e7.54
4.3.1. 2-(Phenylamino)-2-phenylpropanenitrile (Table 3, entry 1)
(d, 2H, J ¼ 8.8 Hz). 13C NMR (CDCl3, 100 MHz):
d 33.5, 55.3, 56.6,
White solid, mp135e136 ꢁC. IR (KBr): 3386, 2925, 2228, 1601,
114.5, 115.8, 119.9, 120.8, 126.1, 128.3, 131.7, 143.5, 159.6. Anal. Calcd.
for C16H16N2O: C, 76.16; H, 6.39; N,11.10. Found: C, 76.22; H, 6.40; N,
11.07.
1512,1314,1260, 871, 695 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d 1.95 (s,
3H), 4.28 (s, 1H), 6.53e6.56 (m, 2H), 6.78e6.83 (m, 1H), 7.10e7.14
(m, 2H), 7.26e7.39 (m, 3H), 7.41e7.64 (m, 2H). 13C NMR (CDCl3,
100 MHz):
d
33.4, 57.1, 115.7, 119.9, 120.1, 124.8, 129.0, 129.2, 139.8,
4.3.8. 2-(Phenylamino)-2-(4-nitrophenyl)propanenitrile (Table 3,
entry 8)
143.4. Anal. Calcd. for C15H14N2: C, 81.05; H, 6.35; N,12.60. Found: C,
81.11; H, 6.37; N, 12.55.
White solid, mp 153e154 ꢁC. IR (KBr): 3380, 2937, 2231, 1604,
1519, 1347, 1263, 746, 695 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d 1.97 (s,
4.3.2. 2-(2-Tolylamino)-2-phenylpropanenitrile (Table 3, entry 2)
3H), 4.42 (s, 1H), 6.48e6.50 (d, 2H, J ¼ 8.4 Hz), 6.82e6.86 (m, 1H),
White solid, mp148e149 ꢁC. IR (KBr): 3441, 2987, 2226, 1600,
7.12e7.26 (m, 2H), 7.81e7.85 (d, 2H, J ¼ 7.6 Hz), 8.25e8.29 (d, 2H,
1507, 1311, 1263, 871, 698 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d
1.98 (s,
J ¼ 7.6 Hz). 13C NMR (CDCl3, 100 MHz):
d 33.0, 56.7, 115.6, 119.7,
3H), 2.27 (s, 3H), 4.09 (s, 1H), 6.33e6.35 (d, 1H, J ¼ 8.4 Hz),
120.6, 124.6, 126.1, 129.2, 142.6, 146.9, 148.1. Anal. Calcd. for
C15H13N3O2: C, 67.40; H, 4.90; N, 15.72. Found: C, 67.31; H, 4.91; N,
15.76.
6.71e6.75 (m, 1H), 6.89e6.93 (m, 1H), 7.09e7.11 (m, 1H), 7.33e7.41
(m, 3H), 7.59e7.61 (m, 2H). 13C NMR (CDCl3, 100 MHz):
d 17.7, 33.7,
56.7, 114.2, 119.5, 120.8, 123.4, 124.8, 126.6, 128.5, 129.2, 130.3, 139.8,
141.3. Anal. Calcd. for C16H16N2: C, 81.32; H, 6.82; N, 11.85. Found: C,
81.39; H, 6.82; N, 11.83.
4.3.9. 2-(4-Tolylamino)-2-(4-chlorophenyl)propanenitrile (Table 3,
entry 9)
White solid, mp 156e157 ꢁC. IR (KBr): 3384, 2993, 2230, 1615,
4.3.3. 2-(4-Tolylamino)-2-phenylpropanenitrile (Table 3, entry 3)
White solid, mp 152e153 ꢁC. IR (KBr): 3386, 3024, 2988, 2226,
1618, 1519, 1302, 1258, 807, 696 cmꢀ1 1H NMR (CDCl3, 400 MHz):
1518, 1302, 1257, 807, 511 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d 1.90 (s,
3H), 2.19 (s, 3H), 4.16 (s, 1H), 6.43e6.54 (d, 2H, J ¼ 8.0 Hz),
6.93e6.95 (d, 2H, J ¼ 8.0 Hz), 7.26e7.39 (d, 2H, J ¼ 8.8 Hz),
d
1.94 (s, 3H), 2.19 (s, 3H), 4.16 (s, 1H), 6.45e6.47 (d, 2H,
J ¼ 8.4 Hz), 6.92e6.94 (d, 2H, J ¼ 8.4 Hz), 7.33e7.42 (m, 3H),
7.62e7.64 (m, 2H). 13C NMR (CDCl3, 100 MHz):
20.4, 33.3, 57.4,
7.55e7.58 (d, 2H, J ¼ 8.8 Hz). 13C NMR (CDCl3, 100 MHz):
d 20.4,
33.2, 56.9, 116.1, 120.4, 126.5, 129.4, 129.6, 129.7, 134.4, 138.7, 140.7.
Anal. Calcd. for C16H15ClN2: C, 70.98; H, 5.58; N, 10.35. Found: C,
70.89; H, 5.57; N, 10.33.
d
116.1, 120.8, 124.9, 128.5, 129.2, 129.4, 129.5, 140.0, 141.0. Anal.
Calcd. for C16H16N2: C, 81.32; H, 6.82; N, 11.85. Found: C, 81.24; H,
6.83; N, 11.88.
4.3.10. 1-(Phenylamino)cyclopentanecarbonitrile (Table 3, entry 10)
White solid, mp 67e68 ꢁC. IR (KBr): 3365, 2982, 2942, 2235,
1602, 1520, 1310, 1258, 747, 691 cmꢀ1 1H NMR (CDCl3, 400 MHz):
4.3.4. 2-(1-Naphthylamino)-2-phenylpropanenitrile (Table 3,
entry 4)
d
1.89e1.92 (m, 4H), 2.12e2.17 (m, 2H), 2.36e2.41 (m, 2H), 3.84 (s,
1H), 6.81e6.89 (m, 3H), 7.23e7.27 (m, 2H). 13C NMR (CDCl3,
100 MHz): 23.8, 40.2, 57.4, 115.6, 119.8, 122.2, 129.3, 144.0. Anal.
White solid, mp 138e139 ꢁC. IR (KBr): 3356, 2991, 2229, 1582,
1526,1401, 1236, 767, 698 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d
2.11 (s,
3H), 4.89 (s, 1H), 6.45e6.47 (d, 1H, J ¼ 7.6 Hz), 7.14e7.18 (m, 1H),
7.31e7.96 (m, 10H). 13C NMR (CDCl3, 100 MHz):
33.7, 56.8, 110.4,
d
Calcd. for C12H14N2: C, 77.38; H, 7.58; N, 15.04. Found: C, 77.44; H,
7.56; N, 15.00.
d

74
X. Hu et al. / Journal of Organometallic Chemistry 705 (2012) 70e74
[20] S. Sipos, I. Jablonkai, Tetrahedron Lett. 50 (2009) 1844e1846.
[21] P. Galletti, M. Pori, D. Giacomini, Eur. J. Org. Chem. (2011) 3896e3903.
[22] J.P. Abell, H. Yamamoto, J. Am. Chem. Soc. 131 (2009) 15118e15119.
[23] S.T. Kadam, P. Thirupathi, S.S. Kim, Synthesis (2011) 919e923.
[24] S. Paraskar, A. Sudalai, Tetrahedron Lett. 47 (2006) 5759e5762.
[25] S.K. De, R.A. Gibbs, Tetrahedron Lett. 45 (2004) 7407e7408.
[26] S.K. De, J. Mol. Catal. A: Chem. 225 (2005) 169e171.
[27] B.C. Ranu, S.S. Dey, A. Hajra, Tetrahedron 58 (2002) 2529e2532.
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[29] B. Das, K. Damodar, B. Shashikanth, Y. Srinivas, I. Kalavathi, Synlett (2008)
3133e3136.
4.3.11. 1-(4-Tolylamino)cyclopentanecarbonitrile (Table 3, entry 11)
White solid, mp 53e54 ꢁC. IR (KBr): 3371, 2959, 2227, 1618, 1518,
1305, 1255, 809, 714 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d 1.82e1.97
(m, 2H), 2.10e2.16 (m, 2H), 2.27e2.42 (m, 4H), 3.73 (s, 1H),
6.74e6.82 (m, 2H), 7.05e7.40 (m, 2H). 13C NMR (CDCl3, 100 MHz):
d
20.4, 23.7, 40.1, 57.9, 116.2, 121.5, 122.4, 125.8, 129.4, 129.7, 141.6.
Anal. Calcd. for C13H16N2: C, 77.96; H, 8.05; N, 13.99. Found: C,
77.94; H, 8.06; N, 14.03.
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4.3.12. 1-(Phenylamino)cyclohexanecarbonitrile (Table 3, entry 12)
White solid, mp 70e71 ꢁC. IR (KBr): 3352, 2927, 2225, 1601,
1497, 1318, 1254, 747, 692 cmꢀ1 1H NMR (CDCl3, 400 MHz):
d
1.27e1.36 (m, 1H), 1.60e1.80 (m, 7H), 2.31e2.35 (m, 2H), 3.64 (s,
1H), 6.88e6.92 (m, 3H), 7.21e7.26 (m, 2H). 13C NMR (CDCl3,
100 MHz): 22.2, 24.8, 36.6, 54.3, 117.5, 120.5, 121.1, 129.2, 143.5.
d
Anal. Calcd. for C13H16N2: C, 77.96; H, 8.05; N, 13.99. Found: C,
78.03; H, 8.04; N, 13.94.
Acknowledgment
The authors thank the National Natural Science Foundation of
China (21162024) for the financial support of this work.
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