Synthesis of new 3-cyanocoumarins with c-6 azo function using ultrasound and grinding techniques in the presence of nano Fe3O4

Article abstract of DOI:10.2174/157017861101140113160517

The first synthesis of azo bearing coumarins from azo aldehydes and malononitrile in the presence of efficient recyclable catalyst, nano particle Fe₃O₄ under ultrasound irradiation and under grinding reaction in high yield and short

Full text of DOI:10.2174/157017861101140113160517

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Letters in Organic Chemistry, 2014, 11, 29-34
29
Synthesis of New 3-Cyanocoumarins with C-6 Azo Function Using Ultra-
sound and Grinding Techniques in the Presence of Nano Fe3O4
Mohammad Nikpassand1*, Leila Zare Fekri2, Narjes Changiz1 and Forouzan Imani1
2
1Department of Chemistry, Rasht Branch, Islamic Azad University, Rasht, Iran; Department of Chemistry, Payame
Noor University, PO Box 19395-3697 Tehran, Iran
Received June 21, 2013: Revised August 26, 2013: Accepted September 05, 2013
Abstract: The first synthesis of azo bearing coumarins from azo aldehydes and malononitrile in the presence of efficient
recyclable catalyst, nano particle Fe3O4 under ultrasound irradiation and under grinding reaction in high yield and short
reaction time is reported. In the other study, the first electrophilic substitution under ultrasound irradiation for the synthe-
sis of azo bearing coumarins was developed. All of synthesized compounds were characterized by IR, NMR and elemen-
tal analysis.
Keywords: Coumarins, nano-Fe3O4, malononitrile, azo aldehydes.
INTRODUCTION
ins in fast and environmentally benign synthetic routes has
created a lot of interest in organic chemistry.
Coumarins are well known natural products for their di-
verse biological activities such as photosensitizers [1], anti-
HIV agents [2], antibiotics [3], rodenticides and oral antico-
agulants [4], inhibitor of platelet aggregation [5], antibacte-
rial [6], anticancer [7] and inhibitor of steroid 5ꢀ- reductase
[8].
In continuation of our studies on the synthesis of hetero-
cyclic compound [22-24], herein, we wish to report our pre-
liminary efforts for the synthesis of new azo containing
coumarin moiety from synthesized aldehydes and malononi-
trile using nano particle Fe3O4 under (i) reflux condition
(boiling water) and (ii) ultrasound irradiation (Scheme 1).
Coumarin derivatives display a broad range of applica-
tions to the pharmaceutical, perfume, cosmetic, food,
agrochemical [9], sensors and sophisticated photophysical
system [10-12], that is, in organic light-emitting diodes [13]
and molecular photonic devices [14] and in the preparation
of insecticides, optical brightening agents, dispersed
fluorescent and tunable dye lasers [15].
RESULTS AND DISCUSSION
Recently organic reactions in water without use of harm-
ful organic solvent have drawn much more attention, be-
cause water is a cheap, safe and environmentally benign sol-
vent. So, we prefer to use water as a green solvent in this
reaction. Initially, we carried out the reaction of 2-hydroxy-
5-(phenyldiazenyl) benzaldehyde (1a) and malononitrile (2)
in the presence of various amount of our synthesized nano-
Fe3O4 [25] (Fig. 1) at reflux condition. The results are
summarized in (Table 1).
Coumarins also act as intermediates for the synthesis
of fluorocoumarins, chromenes, coumarones and 2-acyl-
resorcinols [16].
Coumarins have been synthesized by several routes in-
cluding Pechman [17], Perkin [18], Knovenagel [19], Re-
formatsky [20] and Wittig reaction [21].
Based on the results above, the reaction condition was
optimized to improve the yield and reaction time by chang-
ing the amount of catalyst. As shown in (Table 1), when the
reaction was performed in the absence of catalyst, 57% yield
of product was observed in 4 hours (entry 1, Table 1). How-
ever, when 50 mg of nano particle Fe3O4 was used, the yield
was improved significantly (entry 4, Table 1). The reaction
took much longer reaction time to give 3a when 10 mg or 30
mg of nano Fe3O4 or 50 mg Fe3O4 was involved as catalyst.
Higher amount of catalyst did not further improve the yield
of 3a (entry 5, Table 1).
Various procedures were used for the Perkin synthesis of
coumarins. The main disadvantages of the processes are long
reaction times, low yields, harsh reaction condition and tem-
perature above 150°C, non reusability of the catalyst, use of
excess amount of the reagent, strictly reactive condition (N2
atmosphere), special efforts required to prepare the catalyst
and tedious work up and low selectivity.
However, to the best of our knowledge, no reports con-
cerning coumarins conjugated with azo systems have ap-
peared so far. Hence, synthesis of new generation of coumar-
To investigate the scope of synthesis, different synthe-
sized aldehydes were reacted with malononitrile in the pres-
ence of 50 mg nano particle Fe3O4 at reflux condition and
the results were listed in (Table 2). The reaction preceded
smoothly giving 71-81% yield with various synthesized alde-
*Address correspondence to this author at the Department of Chemistry,
Rasht Branch, Islamic Azad University, Rasht, Iran; Tel: +981314224081;
E-mail: nikpassand@iaurasht.ac.ir
1875-6255/14 $58.00+.00
© 2014 Bentham Science Publishers

30 Letters in Organic Chemistry, 2014, Vol. 11, No. 1
Nikpassand et al.
1
2
R
CHO
R
CN
CN
technique 1:
3
R
N
N
OH
+
1
2
nano- Fe O
3
4
H O
2
)))
1
2
3
3a: R = R = R = H
CN
1
2
3
3b: R = R = H, R = CH
1
3
R
1
2
3
2
3 c: R = R = H, R = OCH
R
3
O
1
2
3
3d: R = R = H, R = Cl
3
1
2
3
R
N
N
O
3e: R = R = H,
R = Br
1
2
3
3 f: R = R = H , R = NO
2
1
2
3
3 g: R = CH , R = H , R = NO
3
3
2
1
2
3
3h: R = NO , R
=
R
3
= H
2
1
2
3 i: R = Cl, R
=
R
= H
)))
1
2
3
3j: R = R = H,
R = I
OH
2
2
1
R
1
R
R
R
OHC
CN
))) NC
technique 2 :
Na NO , H
2
+
3
3
R
N
+
R
NH
2
2
NC
2
)))
O
O
6
7
4
5
Scheme 1. Synthesis of coumarins using nano-Fe3O4.
On the other hand, ultrasound irradiation has been in-
creasingly used in organic synthesis in last three decades.
Comparing with traditional methods, this method is more
conveniently and easily controlled. In the course of our in-
vestigation to develop a green and effective procedure to
reach higher yield, shorter reaction time and milder reaction
condition, we concentrated to synthesize product 3a-j under
ultrasound irradiation. The results were summarized in (Ta-
ble 2). The higher yield and less reaction time during ultra-
sonic irradiation in the presence of the catalyst can be attrib-
uted to implosive collapse of the cavitations period of the
sound waves. When the formed bubbles burst, it results in
high temperature and high pressure which facilitate the in-
termolecular reaction. This is more useful when the solid act
as a catalyst.
Fig. (1). SEM image of synthesized nano-Fe3O4.
In continuation of our studies, we concentrated to synthe-
sis of these compounds by Perkin reaction under grinding.
The results were summarized in (Table 2).
hydes bearing different substituents. Moreover, azo linked
aldehydes containing electron withdrawing group provided
better yields and times than those with electron donating
groups. Electron withdrawing substituents increases the
chemical activity of C=O by the resonance effect for the re-
action with malononitrile nucleophilic attack.
The possible mechanism for the synthesis of 3a in the
presence of nano Fe3O4 as a promoter is shown in (Scheme
2). On the basis of this mechanism, nano Fe3O4 catalyzes the
Table 1. The Optimization of Amount of Catalyst for the Synthesis of 3a at Reflux
Entry
Catalyst
Amount of Catalyst
Time (min)
Yield (%)
1
2
3
4
5
6
none
none
10 mg
30 mg
50 mg
100 mg
50 mg
240
75
57
67
70
76
77
73
Nano Fe3O4
Nano Fe3O4
Nano Fe3O4
Nano Fe3O4
Fe3O4
75
60
60
120

Synthesis of New 3-Cyanocoumarins with C-6 Azo Function
Letters in Organic Chemistry, 2014, Vol. 11, No. 1 31
Table 2. Perkin Synthesis of Azo Conjugated Coumarins 3a-j
Pathway a
Pathway b
Ultrasound
Pathway c
Grinding
Entry
Product
Reflux
Ultrasound
Time (min)
Yield (%)a
Time (min)
Yield (%)a
Time (min)
Yield (%)a, b
Time (s)
Yield (%)a
1
2
3a
3b
3c
3d
3e
3f
60
75
75
60
60
45
75
75
75
60
76
73
79
75
80
81
77
71
75
80
7
9
8
5
5
5
7
8
7
5
89
92
90
95
96
98
86
88
87
96
12(180)c
87(58)c
90
10
15
12
5
92
95
93
94
97
94
87
90
95
97
15
3
10
90
4
8(120)c
94(67)c
5
7
9
97
7
6
95
7
7
3g
3h
3i
13
10
10
9
82
10
12
10
7
8
86
9
88
10
3j
97
a Isolated yield. b Identified by spectroscopic analysis (IR, 1H NMR, 13C NMR and elemental analysis). C the reaction time and yield in reflux condition.
O H
microject of a ldehyde
)))
CH O
ArN
2
O H
H
1
O
Fe O nano particle
3 4
ArN
2
nano-Fe O
3
4
4
CN
CN
2
OH
N
C
ArN
2
CN
H
5
na no -Fe O
3
4
Fe
O nano part icle
4
OH
3
N
C
ArN
2
CN
H
6
O
O
NH
ArN
2
CN
O
3
ArN
2
CN
7
Scheme 2. Proposed pathway for the synthesis of 3-Cyanocoumarins with C-6 azo function.

32 Letters in Organic Chemistry, 2014, Vol. 11, No. 1
Nikpassand et al.
Table 3. Reusability of Nano Fe3O4 for the Synthesis 3a at Reflux Condition
Run of Reusability of Catalyst
Time (min)/ Yield (%)
1
2
3
4
5
7/89
7/89
7/87
7/88
8/85
Knovenagel reaction by the activation of the aldehyde, mak-
ing the carbonyl group susceptible to nucleophilic attack by
malononitrile. The intramolecular treatment of OH to nitrile
group and hydrolysis of intermediate 7 lead to product 3.
470 spectrometer. 1H NMR spectra were recorded on a
Bruker DRX-500 Avance spectrometer in DMSO-d6 as sol-
vent and with TMS as internal standard. Chemicals were
purchased from Merck and Fluka. Elemental analyses were
done on a Carlo-Erba EA1110CNNO-S analyzer and agreed
with the calculated values. All solvents used were dried and
distilled according to standard procedures.
All of the products were fully characterized by spectro-
1
scopic methods (IR and H NMR, 13C NMR and elemental
analysis). All of the products 3 exhibited a singlet in their 1H
NMR spectra at ꢀ = 8.39 – 8.40 ppm for deshield Hꢁ in cou-
marin ring and also a distinguishing peak at ꢀ = 167 ppm for
C=O in their 13C NMR spectra. In IR spectra revealed C-O,
N=N, CN and C=O peak at 1178-1182, 1412-1566, 2225-
2237 and 1731-1739 cm-1.
Preparation of Nano-Fe3O4
For synthesis of Fe3O4 Magnetic nano particle (MNPs),
6.3 g FeCl3.6H2O, 4.0 g FeCl2.4H2O and 1.7 mL HCl (12
mol L-1) were dissolved in 50 mL of deionized water in a
beaker in order to prepare the stock solution of ferrous and
ferric chloride. After that, the solution was degassed with
argon gas and heated to 80 °C in a reactor. Simultaneously,
250 mL of a 1.5 mol L-1 ammonia solution was slowly added
to the solution under argon gas protection and vigorous stir-
ring (1000 rpm). During the whole process, the solution
temperature was maintained at 80 °C and argon gas was
purged to prevent the intrusion of oxygen. After completion
of the reaction, the obtained Fe3O4 MNPs precipitate was
separated from the reaction medium by the magnetic field
and then washed four times with 500 mL doubly distilled
water. Finally, the obtained Fe3O4 MNPs were resuspen-
sioned in 500 mL of degassed deionized water. The obtained
concentration of Fe3O4 MNPs was 6.2 mg mL-1 and the
MNPs were stable in this condition up to one month (Fig. 1).
In order to investigate the reusing performance of nano
particle Fe3O4, the recycle experiment was conducted. The
catalyst was isolated by filtration in the presence of an effi-
cient magnetic bar and could be recycled up to sixth times
without significant loss of activity. The reaction results
which catalyzed by the recycled nano Fe3O4 are shown in
(Table 3).
In the final research, we were interested to synthesize
compound 3 via electrophilic substitution. In this procedure,
initially, the reaction between aldehyde and malononitrile
was carried out, followed by drop-wise addition of dia-
zonium salt to synthesized coumarins under ultrasound irra-
diation. Various derivatives of product 3 were synthesized in
this pathway. The results are summarized in (Table 2). It was
interesting that the reaction time and yield in this new path-
way for the synthesis of 3-Cyanocoumarins with C-6 azo
function were interesting as the former pathway. On the
other hand, this reaction in this new pathway can be done at
room temperature under ultrasound irradiation without any
undesirable byproduct.
General Procedure for the Synthesis of Azo Conjugated
Coumarins 3 in Method 1 Under Ultrasound Irradiation
A mixture of azo aldehyde 1 (1 mmol), malononitrile (1
mmol) and nano particle Fe3O4 (50 mg) were placed into
Pyrex-glass open vessel and irradiated in a water bath under
silent condition by ultrasound (45 kHz) at 60 °C for the re-
quired reaction times (5-9 min). The progress of the reaction
was monitored by TLC (EtOAc: petroleum ether 1:3). Then
the reaction mixture was cooled to room temperature, and
the product was filtered in the presence of an efficient mag-
netic bar to separate of catalyst. The products 3a-j was crys-
tallized from EtOAc to furnish the desired coumarins. The
pure products were collected in 87-98% yields.
CONCLUSION
Nano Fe3O4 is an inexpensive, easily synthesized, non
corrosive and environmentally benign catalyst. Finally, a
convenient and efficient procedure for the preparation of 3-
Cyanocoumarins with C-6 azo function in high yield and
short reaction time and mild condition under ultrasound irra-
diation or grind condition was reported. The electrophilic
substitution reaction reported in this work is mild and a wide
range of functional groups can be tolerated in the synthesis
coumarins. In this pathway, the purification process is much
simplified. Generally, recyclable catalyst, short reaction
times and productivity, availability of reactants, operational
simplicity and easy workup are the notable advantages of
this methodology. To the best of knowledge, this is the first
report on the electrophilic substitution reaction for the syn-
thesis of coumarins.
General Procedure for the Synthesis of Azo Conjugated
Coumarins 3 in Method 2 Under Ultrasound Irradiation
A mixture of various aniline 4 (1 mmol), NaNO2
(1 mmol) and HCl (1mL) were placed into Pyrex-glass open
vessel and irradiated in a water bath under silent condition
by ultrasound (45 kHz) at room temperature for the required
reaction times (5 min). The progress of the reaction was
monitored by TLC (EtOAc: petroleum ether 2:1). Then the
reaction mixture was added in situ dropwise to synthesized
compound 7, and the reaction was irradiated for the required
reaction time (7-15 min) to produce compound 3a-j. Then
EXPERIMENTAL
Materials and Instruments
Melting points were measured on an Electrothermal 9100
apparatus. IR spectra were determined on a Shimadzo IR-

Synthesis of New 3-Cyanocoumarins with C-6 Azo Function
Letters in Organic Chemistry, 2014, Vol. 11, No. 1 33
the reaction mixture was cooled to room temperature, and
the product was filtered without further purification.
Anal. Calcd. for C16H8ClN3O2: C, 62.95; H, 2.60; N, 13.57.
Found: C, 62.98; H, 2.57; N, 13.53
6-((4-Bromophenyl)diazenyl)-2-oxo-2H-chromene-4-carbo-
nitrile 3e
General Procedure for the Synthesis of Azo Conjugated
Coumarins 3 in Method 3 Under Grind Condition
M.p 275°C dec; IR (KBr): 2929, 2237 (CN), 1739
(C=O), 1685, 1652, 1614, 1506 cm-1. 1HNMR (400 MHz,
CDCl3, ppm): ꢀ 7.57 (1H, J = 8.8 Hz, d), 7.72 (2H, J = 8.8
Hz, d), 7.88 (2H, J = 8.8 Hz, d), 8.19 (1H, J = 2.0 Hz, d),
8.33 (1H, J = 8.8 Hz, J = 2.0 Hz, dd), 8.42 (1H, s). 13CNMR
A mixture of azo aldehyde 1 (1 mmol), malononitrile (1
mmol) and nano particle Fe3O4 (50 mg) were added to a
mortar and the mixture was pulverized with a pestle. A spon-
taneous reaction took place (5-15 sec, (Table 2), monitored
by TLC EtOAc: petroleum ether 2:1. After completion of the
reaction, acetone (10 mL) was added, and insoluble reagents
were removed by filtration. The filtrate was evaporated un-
der reduced pressure and the resulting crude material was
purified by recrystalization from EtOAc to afford pure prod-
ucts.
(100 MHz, DMSO-d6, ppm): ꢀ 103.81, 114.88, 118.77,
C
124.98 (two carbons), 126.11, 128.91 (two carbons), 132.56,
132.98, 148.79, 150.98, 153.64, 156.16, 156.97, 167.78.
Anal. Calcd. For C16H8BrN3O2: C, 54.26; H, 2.28; N, 11.86.
Found: C, 54.68; H, 2.56; N, 11.89.
6-((4-Ntrophenyl)diazenyl)-2-oxo-2H-chromene-4-carboni-
trile 3f
2-Oxo-6-(phenyldiazenyl)-2H-chromene-4-carbonitrile 3a
M.p 263°C dec, IR (KBr): 3055, 2231 (CN), 1733
(C=O), 1614, 1560, 1475, 1180 cm-1. 1HNMR (400 MHz,
CDCl3, ppm): ꢀ 7.57-7.62 (4H, m), 7.97-7.99 (2H, m), 8.19
(1H, J = 2.2 Hz, d), 8.33 (1H, J = 8.8 Hz, J = 2.2 Hz, dd),
8.41 (1H, s). 13CNMR (100 MHz, CDCl3, ppm): ꢀ 103.85,
114.90, 118.77, 122.51, 124.93, 128.94, 130.25, 137.11,
148.80, 149.09, 150.71, 153.65, 156.18, 167.98.
M.p 274°C dec; IR (KBr): 3047, 2921, 2231 (CN), 1735
1
(C=O), 1610, 1562, 1463, 1182 cm-1. HNMR (400 MHz,
CDCl3, ppm): ꢀ 7.57 (1H, J = 8.8 Hz, d), 7.71 (2H, J = 8.6
Hz, d), 7.94 (2H, J = 8.4Hz, d), 8.19 (1H, J = 2.0 Hz, d),
8.32 (1H, J = 8.8 Hz, J = 2.2 Hz, dd), 8.40 (1H, s). 13CNMR
(100 MHz, DMSO-d6, ppm): ꢀ 107.23, 116.76, 118.56 (two
carbons), 126.99, 127.09, 128.34, 132.06 (two carbons),
132.56, 148.45, 152.14, 153.67, 156.56, 156.97, 167.87.
Anal. Calcd. For C16H8N4O4: C, 60.00; H, 2.52; N, 17.49.
Found: C, 60.23; H, 2.59; N, 17.88.
2-Oxo-6-(p-tolyldiazenyl)-2H-chromene-4-carbonitrile 3b
M.p 263°C dec, IR (KBr): 3049, 2225 (CN), 1737
1
(C=O), 1608, 1469, 1412, 1103 cm-1. HNMR (400 MHz,
DMSO-d6, ppm): ꢀ 2.50 (3H, s), 7.29 (2H, J = 8.0 Hz, d),
7.55 (1H, J = 8.8 Hz, d), 7.87 (2H, J = 8.0 Hz, d), 8.16 (1H,
J = 2.2 Hz, d), 8.31 (1H, J = 8.8 Hz, J = 2.2 Hz, dd), 8.39
(1H, s). 13CNMR (100 MHz, DMSO-d6, ppm): ꢀ 20.12,
105.63, 115.78, 119.09, 123.11 (two carbons), 124.73,
129.64 (two carbons), 130.16, 139.45, 148.34, 149.87,
150.11, 152.45, 156.90, 166.08. Anal. Calcd. for
C17H11N3O2: C, 70.58; H, 3.83; N, 14.53. Found: C, 70.44;
H, 3.87; N, 14.45.
6-((2-Methyl-4-nitrophenyl)diazenyl)-2-oxo-2H-chromene-
4-carbonitrile 3g
M.p 265°C dec; IR (KBr): 3053, 2229 (CN), 1733
1
(C=O), 1610, 1519, 1429, 1178 cm-1. HNMR (400 MHz,
CDCl3, ppm): ꢀ 2.86 (3H, s), 7.61 (1H, J = 8.8 Hz, d), 7.78
(1H, J = 8.8 Hz, d), 8.18 (1H, J = 8.8 Hz, J = 2.0 Hz, dd),
8.25 (1H, J = 2.0 Hz, d), 8.30 (1H, J = 2.0 Hz, d), 8.35 (1H,
J = 8.8 Hz, J = 2.0 Hz, dd), 8.44 (1H, s). 13CNMR (100
MHz, DMSO-d6, ppm): ꢀ 15.52, 103.86, 114.84, 117.34,
C
118.87, 122.69, 126.90, 128.89, 132.08, 137.53, 139.76,
149.00, 149.19, 153.51, 156.60, 156.92, 162.88. Anal. Calcd.
For C17H10N4O4: C, 61.08; H, 3.02; N, 16.76. Found: C,
61.35; H, 3.26; N, 16.90.
6-((4-Methoxyphenyl)diazenyl)-2-oxo-2H-chromene-4-car-
bonitrile 3c
1
M.p 263°C dec, HNMR (400 MHz, DMSO-d6, ppm): ꢀ
3.96 (3H, s), 7.08 (2H, J = 8.8 Hz, d), 7.53 (1H, J = 8.8 Hz,
d), 7.98 (2H, J = 8.8 Hz, d), 8.12 (1H, J = 2.0 Hz, d), 8.28
(1H, J = 8.8 Hz, J = 2.0 Hz, dd), 8.39 (1H, s). 13CNMR (100
MHz, DMSO-d6, ppm): ꢀ 71.00, 106.33, 118.91, 119.09,
124.01 (two carbons), 126.82, 128.93, 130.65, 138.53,
149.24, 149.87, 151.13, 154.46, 156.89, 167.61. Anal. Calcd.
for C17H11N3O3: C, 70.58; H, 3.83; N, 14.53. Found: C,
70.36; H, 3.78; N, 14.39.
6-((2-Nitrophenyl)diazenyl)-2-oxo-2H-chromene-4-carbo-
nitrile 3h
M.p 265°C dec; IR (KBr): 3040, 2233, 1731, 1608, 1566,
1
1461, 1178 cm-1. HNMR (400 MHz, CDCl3, ppm): ꢀ 7.42
(1H, J = 8.0 Hz, t), 7.50 (1H, J = 6.8 Hz, t), 7.59 (1H, J = 8.9
Hz, d), 7.64 (1H, J = 7.6 Hz, d), 7.77 (1H, J = 2.0 Hz, d),
8.23 (1H, J = 1.8 Hz, d), 8.38 (1H, J = 8.9, J = 1.8 Hz, dd),
8.44 (1H, s). 13CNMR (100 MHz, DMSO-d6, ppm): ꢀ
6-((4-Chlorophenyl)diazenyl)-2-oxo-2H-chromene-4-carb-
onitrile 3d
C
103.84, 114.76, 118.12, 118.68, 118.87, 125.56, 128.79,
131.38, 133.82, 134.79, 142.08, 149.04, 153.68, 156.36,
156.94, 165.98. Anal. Calcd. For C16H8N4O4: C, 60.00; H,
2.52; N, 17.49; Found: C, 60.07; H, 2.43; N, 17.05.
M.p 300°C dec, IR (KBr): 2933, 2233 (CN), 1737
1
(C=O), 1610, 1650, 1510, 1085 cm-1. HNMR (400 MHz,
CDCl3, ppm): ꢀ 7.55 (2H, J = 8.6 Hz, d), 7.59 (1H, J = 8.4
Hz, d), 7.93 (2H, J = 8.6 Hz, d), 8.19 (1H, J = 2.4 Hz, d),
8.32 (1H, J = 8.6 Hz, J = 2.4 Hz, dd), 8.42 (1H, s). 13CNMR
(100 MHz, DMSO-d6, ppm): ꢀ 103.85, 114.90, 118.77,
122.51 (two carbons), 124.93, 128.94, 130.25 (two carbons),
137.11, 148.80, 150.71, 153.65, 156.18, 156.98, 167.65.
6-((2-Chlorophenyl)diazenyl)-2-oxo-2H-chromene-4-carb-
onitrile 3i
M.p 275°C dec; IR (KBr): 3043, 2231 (CꢁN), 1733
1
(C=O), 1610, 1566, 1463, 1178 cm-1. HNMR (400 MHz,

34 Letters in Organic Chemistry, 2014, Vol. 11, No. 1
Nikpassand et al.
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CDCl3, ppm): ꢂ 7.41 (1H, J = 7.2 Hz, t), 7.50 (1H, J = 7.6
Hz, t), 7.58 (1H, J = 8.8 Hz, d), 7.63 (1H, J = 8.0 Hz, d),
7.77 (1H, J = 8.0 Hz, d), 8.23 (1H, J = 1.6 Hz, d), 8.37 (1H,
J = 8.8, 1.6 Hz, d), 8.44 (1H, s). 13CNMR (100 MHz,
DMSO-d6, ppm): ꢀ 106.56, 115.87, 117.81, 118.08, 118.23,
125.67, 129.07, 130.98, 133.22, 137.45, 142.63, 148.46,
154.31, 156.63, 156.94, 165.75. Anal. Calcd. For
C16H8ClN3O2: C, 62.05; H, 2.60; N, 13.57; Found: C, 62.25;
H, 2.24; N, 13.41.
6-((4-Iodophenyl)diazenyl)-2-oxo-2H-chromene-4-carbo-
nitrile 3j
[9]
M.p 288°C dec; IR (KBr): 3080, 2231 (CꢃN), 1735
[10]
1
(C=O), 1610, 1560, 1461, 1182 cm-1. HNMR (400 MHz,
CDCl3, ppm): ꢂ 7.57 (1H, J = 8.8 Hz, d), 7.77 (2H, J = 8.8
Hz, d), 7.94 (2H, J = 8.8 Hz, d), 8.19 (1H, J = 2.2 Hz, d),
8.32 (1H, J = 8.8, J = 2.2 Hz, dd), 8.40 (1H, s). 13CNMR
(100 MHz, DMSO-d6, ppm): ꢀ 100.33, 103.38 (two car-
bons), 114.85, 118.85 (two carbons), 124.99, 129.14, 132.16,
139.05, 148.81, 151.41, 153.65, 156.14, 156.97, 167.49.
Anal. Calcd. For C16H8IN3O2: C, 47.90; H, 2.01; N, 10.47;
Found: C, 47.57; H, 2.18; N, 10.23.
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CONFLICT OF INTEREST
The authors confirm that this article content has no
conflicts of interest.
[15]
[16]
ACKNOWLEDGEMENTS
Declared none.
[17]
SUPPLEMENTARY MATERIAL
[18]
[19]
[20]
[21]
Supplementary material is available on the publishers
Web site along with the published article.
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