An efficient synthesis of 2-amino-4-aryl-6,7,8,9-tetrahydro-5H-benzo[7] annulene-1,3-dicarbonitriles in THF with DBU as catalyst

Article abstract of DOI:10.1007/s11164-012-0491-3

An efficient and convenient multicomponent reaction for preparation of 2-amino-4-aryl-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-dicarbonitrile derivatives, in THF, with DBU as catalyst is reported. These compounds are typical acceptor-donor-acceptor (A-D

Full text of DOI:10.1007/s11164-012-0491-3

Res Chem Intermed (2012) 38:1647–1654
DOI 10.1007/s11164-012-0491-3
An efficient synthesis of 2-amino-4-aryl-6,7,8,9-
tetrahydro-5H-benzo[7]annulene-1,3-dicarbonitriles
in THF with DBU as catalyst
•
Liangce Rong Shimin Tao Sheng Xia Lihua Liu
•
•
•
•
Shan Yin Yanhui Shi
Received: 15 November 2011 / Accepted: 17 January 2012 / Published online: 28 January 2012
Ó Springer Science+Business Media B.V. 2012
Abstract An efficient and convenient multicomponent reaction for preparation of
2-amino-4-aryl-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-dicarbonitrile deriva-
tives, in THF, with DBU as catalyst is reported. These compounds are typical
acceptor–donor–acceptor (A–D–A) systems comprising one electron donor and two
electron acceptors with different important chemical properties. Excellent yields
and the simplicity of the reaction procedure make this one of the most efficient
methods for synthesis of these types of compound.
Keywords 2-Amino-1,3-dicarbonitriles Á Optical properties Á DBU Á
Benzo[7]annulene
Introduction
Multifunctionalized benzenes containing the 2-amino-1,3-dicarbonitrile group (I),
are typical acceptor–donor–acceptor (A–D–A) systems comprising one electron
donor and two electron acceptors. These are not only important constituents of a
large number of bioactive compounds [1–3], but are also useful as versatile
precursors for asymmetric synthesis [4]. They are, furthermore, also very important
compounds because of their optical properties [5] and are the basis for artificial
photosynthetic systems [6, 7], materials with semiconducting or nonlinear optical
properties [8], and molecular electronic devices [9]. Different types 2-amino-1,3-
dicarbonitrile compounds have been synthesized. Aromatic aldehydes and aromatic
ketones reacted with malononitrile give 4,6-diaryl-2-amino-1,3-dicarbonitriles
L. Rong (&) Á S. Tao Á S. Xia Á L. Liu Á S. Yin Á Y. Shi
College of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic
Chemistry For Functional Materials, Xuzhou Normal University, Xuzhou 221116, Jiangsu,
People’s Republic of China
e-mail: lcrong2005@yahoo.com
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L. Rong et al.
[10, 11]. Acetone, aromatic aldehydes, and malononitrile react together to give
similar 2-amino-1,3-dicarbonitrile compounds, for example 5-methyl-4-aryl-2-
amino-1,3-dicarbonitriles [12]. Reaction of cyclopentanone [13], cyclohexanone
[14], 2,3-dihydroinden-1-one [15], 3,4-dihydronaphthalen-1(2H)-one [16], or
6,7,8,9-tetrahydrobenzo[7]annulen-5-one [17] with an aldehyde and malononitrile
furnish the corresponding fused polycyclic compounds containing the 2-amino-1,3-
dicarbonitriles. However, in literature reports, cycloheptanone has seldom been used
for synthesis of the corresponding 2-amino-1,3-dicarbonitrile compounds. In the
literature investigated we found only two papers on the synthesis of similar
compounds, those by Elgemeie et al. [18] and Kurbatov et al. [19]. Elgemeie et al.
reported initial condensation of cycloheptanone and malononitrile to give cycloalk-
ylidenemalononitriles then reaction of these condensation products with an
arylmethylenecyanoacetamide, a condensation product from reaction of an aromatic
aldehyde and cyanoacetamide, to give four products in moderate yield. Kurbatov
reported reaction of an aromatic aldehyde and malononitrile to give the condensation
product benzylidenemalononitrile, then reaction of this with malononitrile to give
only one product, 2-amino-4-phenyl-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile. In these two methods, the condensation products of cycloheptanone
and malononitrile or of aromatic aldehyde and malononitrile should be synthesized
first, then reacted with another substrate to product 2-amino-1,3-dicarbonitriles, so
these are, indeed, multistep reactions.
1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) [20–22], an efficient organic basic
catalyst, is often used in organic synthesis. In continuation of our recent studies on the
reaction of multifunctionalized benzenes with 2-amino-1,3-dicarbonitrile compounds
[11, 14, 15], herein we report an efficient one-pot synthesis of 2-amino-4-aryl-6,7,8,9-
tetrahydro-5H-benzo[7]annulene-1,3-dicarbonitrile derivatives in THF in the pres-
ence of DBU as catalyst.
R
A
D
n
A
I
Results and discussion
Before conducting this synthesis, we optimized the reaction conditions. Cyclohep-
tanone (1), 4-fluorobenzaldehyde (2b) and malononitrile (3) were chosen as starting
materials for the model reaction (Scheme 1).
The model reaction was examined in different solvents in the presence of DBU.
H2O, CH3CN, CH3OH, EtOH, THF, etc., were used under reflux conditions and
123

An efficient synthesis
1649
F
Scheme 1 Synthesis of
2-amino-4-(4-fluorophenyl)-
6,7,8,9-tetrahydro-5H-
benzo[7]annulene-1,3-
dicarbonitrile
CHO
O
CN
CN
3
DBU THF
2h
CN
+
+
NH2
F
2b
CN
4b
1
DMF was used at 100 °C to find the best reaction conditions. We found the reaction
could not be conducted in H2O. In the above-mentioned organic solvents, however,
the reaction occurred with different yields. Taken into account overall conditions,
THF was chosen as optimum solvent of this synthesis. The reaction was then
repeated in THF at different temperatures. The results are listed in Table 1. As
shown in Table 1, the best results were obtained in THF under reflux (Entry 6). We
also found that in the absence of DBU in the THF, the reaction did not occur (Entry
10). Of course, other catalysts were also tested in THF, but these gave the inferior
results to DBU.
Having established the optimum conditions for this one-pot reaction, we
investigated the reactions (Scheme 2) of cycloheptanone, different aromatic
aldehydes, and malononitrile under the chosen conditions as indicated in Table 1
entry 6. The results of the reactions are listed in Table 2. We can see from Table 2
that in all the reactions aromatic aldehydes 2 bearing electron-donating groups
(CH3, CH3O) and electron-withdrawing groups (F, Cl, Br) give the desired products
in good yields. Furthermore, heterocyclic aldehydes, for example picolinaldehyde
Table 1 Synthesis of 4b under different conditions
Entry
Catalyst
Solvent
Time (h) Tempa
Yields (%)
1
DBU
DBU
DBU
DBU
DBU
DBU
DBU
DBU
DBU
–
H2O
3
0
25
32
35
16
79
80
10
33
0
2
CH3CN
CH3OH
EtOH
DMF
THT
THF
2
3
2
4
2
5
2 (100 °C)
2
6
7
3
8
THF
2 (0 °C)
2 (25 °C)
2
2
2
9
THT
10
11
12
THT
Et3N
THF
30
26
C5H11
N
THF
Reaction conditions: cycloheptanone (1 mmol), 4-fluorobenzaldehyde (1 mmol), malononitrile
(2.5 mmol), catalyst (0.1 mmol), solvent (10 mL), reaction temperature: reflux
The bold characters indicate the optimum conditions
a
Unless explicitly stated, the reaction was conducted under reflux conditions
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L. Rong et al.
Scheme 2 Synthesis of
2-amino-1,3-dicarbonitriles
R
O
CHO
CN
CN
3
DBU
THF
CN
+
+
R
NH2
CN
4
1
2
Table 2 Results of synthesis of 2-amino-1,3-dicarbonitriles
Entry
Ar
Products
Time (h)
Yields (%)
1
C6H5
4a
4b
4c
4d
4e
4f
2
79
81
76
75
83
85
81
77
80
77
71
2
4-FC6H4
2
3
4-BrC6H4
2
4
4-ClC6H4
2
5
3,4-Cl2C6H3
4-CH3C6H4
3,4-(CH3)2C6H3
3,4-(CH3O)2C6H3
3,4,5-(CH3O)3C6H2
Pyridin-3-yl
2-Thiophenyl
2
6
2.5
2.5
2.2
2
7
4g
4h
4i
8
9
10
11
4j
2
4k
2
and thiophene-2-carbaldehyde, could also be used for synthesis of the target
products.
The structures of compounds 4a–4k were determined by consideration of their
IR, 1H NMR and high-resolution mass spectra (HRMS). For example, the 1H NMR
spectrum of 4a contains a broad singlet at delta 1.39 (2H), a triplet at delta 1.66 (2H,
J = 0.8 Hz), 1.73 (2H, J = 0.8 Hz), 2.39 (2H, J = 3.6 Hz), doublets at delta 3.03
(J = 7.2 Hz) due to the CH2 protons of aliphatic carbon, a singlet at delta 6.42 (2H)
due to NH2 protons, doublets at delta 7.24 (2H, J = 7.2 Hz) and a multiplet at delta
7.47-7.52 (3H) due to five phenyl protons. In HRMS, the calculated m/z for
C19H17N3 [M ? H]? is 288.1501, and we found the experimental m/z was
288.1503.
Conclusions
In conclusion, we have developed a facile and efficient method for synthesis of
2-amino-4-aryl-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-dicarbonitriles via a
three-component reaction of different aromatic aldehydes, cycloheptanone, and
malononitrile in THF with DBU as catalyst. This process has several advantages
including excellent yields, simple operation, and mild conditions. Most of the
products in the text are newly reported.
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An efficient synthesis
1651
Experimental
Melting points were determined on an XT-5 microscopic melting-point apparatus
and are uncorrected. IR spectra were recorded on a FT Bruker Tensor 27
1
spectrometer. H NMR spectra were obtained from solution in DMSO-d6, with
Me4Si as internal standard, using a Bruker-400 spectrometer. HRMS spectra were
obtained with a Bruker microTOF-Q 134 instrument.
General procedure for synthesis of 2-amino-4-aryl-6,7,8,9-tetrahydro-5H-
benzo[7]annulene-1,3-dicarbonitriles
A mixture of cycloheptanone 1 (1 mmol), aromatic aldehyde 2 (1 mmol),
malononitrile 3 (2.5 mmol), THF (10 mL), and DBU (0.01 mmol) was placed in
a reaction flask under reflux conditions. After completion (monitored by TLC), the
reaction mixture was poured into water, filtered, then washed thoroughly with water.
The products were dried and recrystallized from 95% ethanol.
2-amino-4-phenyl-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-dicarbonitrile (4a)
Melting point 209–210 °C (lit [19]. 218 °C); IR (KBr, m, cm-1): 3,408, 3,348,
3,252, 2,928, 2,856, 2,220, 1,698, 1,684, 1,658, 1,635, 1,559, 1,541, 1,521, 1,507,
1
1,497, 1,457, 1,444, 1,363, 1,294, 1,249, 1,200, 964, 704, 669 cm-1; H NMR
(400 MHz, DMSO-d6) (d, ppm): 1.39 (2H, br, CH2), 1.66 (2H, t, J = 0.8 Hz, CH2),
1.73 (2H, t, J = 0.8 Hz, CH2), 2.39 (2H, t, J = 3.6 Hz, CH2), 3.03 (2H, d,
J = 7.2 Hz, CH2), 6.42 (2H, s, NH2), 7.24 (2H, d, J = 7.2 Hz, ArH), 7.47–7.52
(3H, m, ArH); HRMS m/z calculated for C19H17N3 [M ? H]?: 288.1501, Found:
288.1503.
2-amino-4-(4-fluorophenyl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4b)
Melting point 218–220 °C; IR (KBr, m, cm-1): 3,408, 3,351, 3,253, 2,964, 2,930,
2,221, 1,660, 1,607, 1,562, 1,466, 1,456, 1,295, 1,249, 1,222, 1,198, 1,160, 965,
836, 535 cm-1; 1H NMR (400 MHz, DMSO-d6) (d, ppm): 1.41 (2H, t, J = 2.0 Hz,
CH2), 1.65–1.67 (2H, m, CH2), 1.72 (2H, d, J = 3.6 Hz, CH2), 2.37–2.39 (2H, m,
CH2), 3.01-3.03 (2H, m, CH2), 6.44 (2H, s, NH2), 7.32 (2H, t, J = 8.8 Hz, ArH),
7.32 (2H, t, J = 8.8 Hz, ArH); HRMS m/z calculated for C19H16FN3 [M ? Na]?:
328.1226, Found: 328.1230.
2-amino-4-(4-bromophenyl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4c)
Melting point 234–235 °C; IR (KBr, m, cm-1): 3,442, 3,345, 3,242, 2,933, 2,854,
2,225, 1,646, 1,598, 1,531, 1,490, 1,473, 1,392, 1,366, 1,349, 1,339, 1,265, 1,231,
1,211, 1,153, 1,128, 1,103, 1,073, 1,010, 965, 906, 825, 786, 765, 671, 512 cm-1
;
1H NMR (400 MHz, DMSO-d6) (d, ppm): 1.40 (2H, t, J = 4.0 Hz, CH2), 1.63 (2H,
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L. Rong et al.
d, J = 4.8 Hz, CH2), 1.71 (2H, d, J = 4.4 Hz, CH2), 2.24 (2H, dd, J = 5.2 Hz,
J = 5.6 Hz, CH2), 2.83 (2H, dd, J = 5.2 Hz, J = 6.4 Hz, CH2), 7.26 (2H, d,
J = 8.4 Hz, ArH), 7.74 (2H, d, J = 8.4 Hz, ArH); HRMS m/z calculated for
C19H16BrN3 [M ? Na]?:388.0425, Found: 388.0435.
2-amino-4-(4-chlorophenyl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4d)
Melting point 228–230 °C (lit [18]. 230 °C); IR (KBr, m, cm-1): 3,291, 3,130,
2,933, 2,856, 2,225, 1,646, 1,599, 1,531, 1,494, 1,473, 1,441, 1,396, 1,363, 1,349,
1,339, 1,299, 1,266, 1,232, 1,211, 1,192, 1,154, 1,129, 1,088, 1,072, 1,014, 965,
1
906, 890, 861, 841, 828, 787, 766, 709, 671, 628, 562, 526, 515 cm-1; H NMR
(400 MHz, DMSO-d6) (d, ppm): 1.40 (2H, d, J = 4.4 Hz, CH2), 1.63 (2H, d,
J = 4.4 Hz, CH2), 1.71 (2H, d, J = 4.8 Hz, CH2), 2.23–2.26 (2H, m, CH2),
2.82–2.85 (2H, t, J = 5.6 Hz, CH2), 7.33 (2H, d, J = 8.4 Hz, ArH), 7.60 (2H, d,
J = 8.4 Hz, ArH); HRMS m/z calculated for C19H16ClN3 [M ? Na]?: 344.0930,
Found: 344.0933.
2-amino-4-(3,4-dichlorophenyl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4e)
Melting point 176–178 °C; IR (KBr, m, cm-1): 3,257, 3,153, 2,939, 2,911, 2,861,
2,845, 2,184, 2,151, 1,644, 1,608, 1,543, 1,509, 1,490, 1,472, 1,449, 1,407, 1,364,
;
1,335, 1,319, 1,242, 1,204, 1,159, 1,132, 985, 966, 938, 670 cm-1 1H NMR
(400 MHz, DMSO-d6) (d, ppm): 1.32–1.39 (2H, m, CH), 1.43–1.50 (2H, m, CH2),
1.92 (2H, t, J = 5.6 Hz, CH), 2.62–2.65 (2H, m, CH2), 3.25 (2H, br, CH2), 6.40
(2H, s, NH2), 7.39 (1H, d, J = 6.4 Hz, ArH), 7.53 (1H, d, J = 8.4 Hz, ArH); 7.66
(1H, s, ArH); HRMS m/z calculated for C19H15Cl2N3 [M ? H]?: 356.0721, Found:
356.0732.
2-amino-4-p-tolyl-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-dicarbonitrile (4f)
Melting point 230–232 °C; IR (KBr, m, cm-1): 3,408, 3,350, 3,252, 2,963, 2,929,
2,858, 2,220, 1,658, 1,606, 1,561, 1,511, 1,466, 1,455, 1,423, 1,365, 1,352, 1,294,
;
1,248, 1,221, 1,198, 1,159, 1,097, 1,013, 964, 835, 558, 534 cm-1 1H NMR
(400 MHz, DMSO-d6) (d, ppm): 1.38–1.40 (2H, m, CH2), 1.62–1.65 (2H, m, CH2),
1.71–1.72 (2H, m, CH2), 2.25–2.27 (2H, m, CH2), 2.38 (3H, s, CH3), 2.81–2.83 (2H,
m, CH2), 7.15 (2H, d, J = 8.0 Hz, ArH), 7.33 (2H, d, J = 7.6 Hz, ArH); Anal.
calcd for C20H19N3: C, 79.70; H, 6.35; N, 13.94; found C 79.75 H 6.37, N 13.89;
HRMS m/z calculated for C20H19N3 [M ? Na]?: 324.1477, Found: 324.1485.
2-amino-4-(3,4-dimethylphenyl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4g)
Melting point 176.5–177.8 °C; IR (KBr, m, cm-1): 3,353, 3,246, 2,931, 2,856, 2,768,
2,214, 1,686, 1,647, 1,559, 1,501, 1,491, 1,459, 1,364, 1,319, 1,293, 1,249, 1,200,
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962, 875, 837, 821 cm-1; 1H NMR (400 MHz, DMSO-d6) (d, ppm): 1.36–1.40 (2H,
m, CH2), 1.64 (2H, t, J = 4.0 Hz, CH2), 1.69–1.73 (2H, m, CH2), 2.27 (3H, s, CH3),
2.28 (3H, s, CH3), 2.39 (2H, t, J = 5.6 Hz, CH2), 3.01 (2H, t, J = 5.2 Hz, CH2),
6.38 (2H, s, NH2), 6.94 (1H, d, J = 7.6 Hz, ArH), 7.00 (1H, s, ArH), 7.25 (1H, d,
J = 7.6 Hz, ArH); Anal. calcd for C21H21N3: C, 79.97; H, 6.71; N, 13.32; found C
79.92, H 6.70, N 13.42; HRMS m/z calculated for C21H21N3 [M ? Na]?: 338.1633,
Found: 338.1635.
2-amino-4-(3,4-dimethoxyphenyl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4h)
Melting point 226–228 °C; IR (KBr, m, cm-1): 3,420, 3,351, 3,252, 2,955, 2,923,
2,854, 2,217, 1,655, 1,605, 1,587, 1,560, 1,518, 1,455, 1,407, 1,319, 1,294, 1,257,
1
1,236, 1,201, 1,186, 1,156, 1,139, 1,023, 814 cm-1; H NMR (400 MHz, DMSO-
d6) (d, ppm): 1.43–1.44 (2H, m, CH2), 1.63–1.67 (2H, m, CH2), 1.73–1.74 (2H, m,
CH2), 2.44 (2H, t, J = 4.8 Hz, CH2), 3.01 (2H, t, J = 4.8 Hz, CH2), 3.74 (3H, s,
OCH3), 3.82 (3H, s, OCH3), 6.37 (2H, s, NH2), 6.77 (1H, d, J = 8.0 Hz, ArH), 6.82
(1H, d, J = 1.2 Hz, ArH), 7.06 (1H, d, J = 8.0 Hz, ArH); Anal. calcd for
C21H21N3O2: C, 72.60; H, 6.09; N, 12.10; found C 72.62, H 6.08, N 12.19; HRMS
m/z calculated for C21H21N3O2 [M ? H]?: 348.1712, Found: 348.1713.
2-amino-4-(3,4,5-trimethoxyphenyl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4i)
Melting point 230.0–232.7 °C; IR (KBr, m, cm-1): 3,445, 3,355, 3,246, 2,920, 2,846,
2,215, 1,699, 1,685, 1,648, 1,558, 1,542, 1,509, 1,465, 1,412, 1,374, 1,292, 1,244,
1
1,203, 1,153, 1,125, 1,011, 967 cm-1; H NMR (400 MHz, DMSO-d6) (d, ppm):
1.47 (2H, s, CH2), 1.65 (2H, s, CH2), 1.75 (2H, d, J = 0.8 Hz, CH2), 2.44 (2H, d,
J = 6.8 Hz, CH2), 3.02 (2H, t, J = 4.0 Hz, CH2), 3.73 (3H, s, OCH3), 3.77 (6H, s,
2XOCH3), 6.42 (2H, s, NH2), 6.56 (2H, d, J = 2.0 Hz, ArH); Anal. calcd for
C22H23N3O3: C, 70.01; H, 6.14; N, 11.13; found C 70.09, H 6.16, N 11.11; HRMS
m/z calculated for C22H23N3O3 [M ? Na]?: 400.1637, Found: 400.1642.
2-amino-4-(pyridin-3-yl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4j)
Melting point 216.7–218.7 °C; IR (KBr, m, cm-1): 3,444, 3,348, 3,249, 2,925, 2,849,
2,769, 2,219, 1,686, 1,654, 1,632, 1,560, 1,544, 1,524, 1,509, 1,491, 1,460, 1,439,
1
1,420, 1,365, 1,321, 1,297, 1,250, 1,200, 1,145, 1,090, 1,049, 993, 962 cm-1; H
NMR (400 MHz, DMSO-d6) (d, ppm): 1.40 (2H, s, CH2), 1.65 (2H, d, J = 0.4 Hz,
CH2), 1.72 (2H, s, CH2), 2.34 (2H, t, J = 2.4 Hz, CH2), 3.04 (2H, d, J = 0.8 Hz,
CH2), 6.48 (2H, s, NH2), 7.43 (1H, d, J = 7.6 Hz, ArH), 7.49 (1H, t, J = 5.6 Hz,
ArH), 7.96 (1H, t, J = 7.6 Hz, ArH), 8.71 (1H, d, J = 3.6 Hz, ArH); Anal. calcd for
C18H16N4: C, 74.98; H, 5.59; N, 19.43; found C 74.82, H 5.56, N 19.49; HRMS
m/z calculated for C18H16N4 [M ? Na]?: 311.1273, Found: 311.1267.
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2-amino-4-(thiophen-2-yl)-6,7,8,9-tetrahydro-5H-benzo[7]annulene-1,3-
dicarbonitrile (4k)
Melting point 275–276 °C; IR (KBr, m, cm-1): 3,425, 2,937, 2,227, 2,193, 1,698,
1,684, 1,654, 1,616, 1,557, 1,541, 1,521, 1,474, 1,457, 1,421, 1,364, 1,251, 1,066,
1
1,012, 669 cm-1; H NMR (400 MHz, DMSO-d6) (d, ppm): 1.12–1.25 (2H, m,
CH2), 1.34–1.51 (2H, m, CH), 1.65–1.73 (3H, m, CH2, CH), 2.01–2.12 (1H, m, CH),
2.23–2.27 (1H, m, CH), 3,32 (1H, d, J = 7.2 Hz, CH), 7.58 (1H, d, J = 8.0 Hz,
ArH), 7.81–7.86 (1H, m, ArH), 8.28 (1H, d, J = 8.0 Hz, ArH). HRMS m/z calculated
for C17H15N3S [M ? Na]?: 316.0884, Found: 316,0889.
Acknowledgments We are grateful to the National Natural Science Foundation of China (NSFC)
(21172188) and the Foundation of Xuzhou Normal University (10XLS02) for financial support.
References
1. T.J.J. Mu¨ller, U.H.F. Bunz (eds.), Functional Organic Materials, Synthesis, Strategies and Appli-
cations (Wiley-VCH, Weinheim, 2007)
2. R.H. Thomson, The Chemistry of Natural Products (Blackie, Glasgow, 1985)
3. F.V. Singh, R. Vatsyayan, U. Roy, A. Goel, Bioorg. Med. Chem. Lett. 16, 2734 (2006)
4. N.G. Andersen, S.P. Maddaford, B.A. Keay, J. Org. Chem. 61, 9556 (1996)
5. J. Sepiol, P. Milart, Tetrahedron 41, 5261 (1985)
6. M.A. Fox, M. Chanon (eds.), Photoinduced Electron Transfer (Elsevier, Amsterdam, 1988)
7. H. Kurreck, M. Huber, Angew. Chem. Int. Ed. Engl. 34, 849 (1995)
8. P.N. Prasad, D.J. Williams, Introduction to Nonlinear Optical Effects in Molecules and Polymers
(Wiley, New York, 1991)
9. M.C. Petty, M.R. Bryce, D. Bloor (eds.), Introduction to Molecular Electronics (Oxford University
Press, New York, 1995)
10. Z.R. Yu, D. Velasco, Tetrahedron Lett. 40, 3229 (1999)
11. L.C. Rong, H.X. Han, F. Yang, H. Yao, H. Jiang, S.J. Tu, Synth. Commun. 37, 3767 (2007)
12. A. Mehdi, M. Bagher, A. Samira, R.B. Hamid, L.G. Zhu, Synthesis 9, 1526 (2010)
13. S.L. Cui, X.F. Lin, Y.G. Wang, J. Org. Chem. 70, 2866 (2005)
14. L.C. Rong, H.X. Han, H. Jiang, S.J. Tu, Synth. Commun. 38, 3530 (2008)
15. L.C. Rong, H.X. Han, H. Jiang, S.J. Tu, Synth. Commun. 39, 3493 (2009)
16. X.S. Wang, M.M. Zhang, Q. Li, C.S. Yao, S.J. Tu, Tetrahedron 63, 5265 (2007)
17. A.E.G. Hammama, N.A.A. El-Hafeza, W.H. Midurab, M. Mikolajczyk, Z. Naturforsch, B. Chem.
Sci. 55, 417 (2000)
18. G.E.H. Elgemeie, A.M. Elzanate, A.K. Mansour, J. Chem. Soc. Perkin Trans. 1, 1074 (1992)
19. E.S. Kurbatov, V.V. Krasnikov, V.V. Mezheritskii, Russ. J. Org. Chem. 42, 460 (2006)
20. F. Wang, S.J. Cai, Z.P. Wang, C.J. Xi, Org. Lett. 13, 3202 (2011)
21. Z.Q. Rong, M.Q. Jia, S.L. You, Org. Lett. 13, 4080 (2011)
22. S.M. Dumbris, D.J. Di’az, L. McElwee-White, J. Org. Chem. 74, 8862 (2009)
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