Convenient synthesis of a new series of 3-triazolonyl iminocoumarins

Article abstract of DOI:10.1080/00397910903026681

3-Cyano-7-diethylamino-N-ethoxycarbonyl-iminocoumarin reacted with different hydrazines as N-nucleophiles to afford, in one step, a new series of 2-N-substituted 3-triazolonyl-iminocoumarins in good yields. In two cases, N-unsubstituted derivatives were also obtained. The structures of all the products obtained were confirmed by infrared, 1H NMR, 13C NMR, and elemental analysis. The optical properties of three of these compounds in dichloromethane and ethanol were reported.

Full text of DOI:10.1080/00397910903026681

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Convenient Synthesis of a New Series of
3-Triazolonyl Iminocoumarins
Myriam Kammoun a , Hamida Turki a , Suzanne Fery-Forgues b &
Rachid El Gharbi a
a Laboratoire de Chimie Appliquée: Hétérocycles, Corps Gras et
Polymères, Faculté des Sciences de Sfax, Sfax, Tunisia
b Laboratoire des Interactions Moléculaires Réactivité Chimique et
Photochimique, Université Paul Sabatier, Toulouse, France
Version of record first published: 22 Feb 2010
To cite this article: Myriam Kammoun, Hamida Turki, Suzanne Fery-Forgues & Rachid El Gharbi
(2010): Convenient Synthesis of a New Series of 3-Triazolonyl Iminocoumarins, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry,
40:6, 888-900
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Synthetic Communications1, 40: 888–900, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903026681
CONVENIENT SYNTHESIS OF A NEW SERIES OF
3-TRIAZOLONYL IMINOCOUMARINS
Myriam Kammoun,1 Hamida Turki,1 Suzanne Fery-Forgues,2
and Rachid El Gharbi1
1
´
´ ´
Laboratoire de Chimie Appliquee: Heterocycles, Corps Gras et Polymeres,
Faculte des Sciences de Sfax, Sfax, Tunisia
`
´
2
´
´
´
Laboratoire des Interactions Moleculaires Reactivite Chimique et
Photochimique, Universite Paul Sabatier, Toulouse, France
´
3-Cyano-7-diethylamino-N-ethoxycarbonyl-iminocoumarin
reacted
with
different
hydrazines as N-nucleophiles to afford, in one step, a new series of 2-N-substituted
3-triazolonyl-iminocoumarins in good yields. In two cases, N-unsubstituted derivatives were
also obtained. The structures of all the products obtained were confirmed by infrared,
1H NMR, 13C NMR, and elemental analysis. The optical properties of three of these
compounds in dichloromethane and ethanol were reported.
Keywords: Iminocoumarin; spectroscopic properties; 3-triazolonyl iminocoumarin
INTRODUCTION
Coumarins (2-oxo-2H-1-benzopyrans) have been extensively investigated with
regard to their interest as fluorescent dyes[1,2] and biologically active compounds.[3–5]
The 2-imino analogs (2-imino-2H-1-benzopyrans) are less known and were
considered for a long time as an intermediate in the synthesis of coumarins.[6] In
the past decade, many articles dealing with their synthesis and reactivity have been
published.[7–22] Some compounds of this family have found nice applications in the
field of fluorescent sensors,[23,24] and others are promising antimicrobial agents.[25,26]
Above all, the past few years have seen a burst of interest in these compounds
because of their use as starting materials in elaborate condensed heterocyclic com-
pounds[10–14] and functionalized coumarins[15–22] that may exhibit original biological
activities. In particular, it seems that the presence of a hetaryl moiety on the
3-position of the coumarinic system induces specific activities,[27] and use of imino-
coumarins is part of the best routes to access these compounds, which are quite
difficult to obtain otherwise.
During the past few years, the synthesis and reactivity of 3-cyano-
iminocoumarin and its derivatives have attracted our attention. O’Callaghan et al.
Received January 6, 2009.
Address correspondence to Hamida Turki, Laboratoire de Chimie Appliquee: Heterocycles, Corps
´ ´ ´
Gras et Polymeres, Faculte des Sciences de Sfax, 3038 Sfax, Tunisia. E-mail: tur.hamida@yahoo.fr
`
´
888

NEW SERIES OF 3-TRIAZOLONYL IMINOCOUMARINS
889
described the cyclization of 3-cyano-iminocoumarin into fused heterocycles under
the action of C-nucleophilic reagent.[14] In a recent study dealing with ethoxycarbo-
nylated cyano-iminocoumarins, we found that these compounds are convenient
starting materials to provide polyheterocyclic systems when treated with various
nucleophilic or electrophilic reagents. More precisely, we showed that they are read-
ily recyclized by amines and hydrazides of carboxylic acids used as N-nucleophiles to
give 2-oxo-2H-1-benzopyrano-[2,3-d]-pyrimidines bearing an arylamino or acylhy-
drazino fragment in the 4-position.[28,29] As a continuation of our studies, we inves-
tigate here the interaction of N-ethoxycarbonylated iminocoumarin with hydrazines
to determine new synthetic capabilities. We chose to work with hydrazines that bear
an arylhalogenated group because it has been known for long that coumarin deriva-
tives provided with this type of substituent exhibit strong activity as anticoagulant
rodenticides[30,31] and anti-inflammatory agents.[4,32] The present article describes
an ‘‘unusual’’ reaction of 3-cyano-7-diethylamino-N-ethoxycarbonyl-iminocoumarin
1 with various hydrazines as an efficient way to obtain a new series of iminocoumar-
ins containing a triazolonic heterocycle in the 3-position. To the best of our knowl-
edge, triazolonyl iminocoumarins are unknown, and they might exhibit interesting
biological activities. The optical properties of some of these new 3-hetaryl iminocou-
marins are also described.
RESULTS AND DISCUSSION
Synthesis
3-Cyano-iminocoumarin 1 was obtained by Knoevenagel protocol followed by
N-ethoxycarbonylation as already described in previous work[28] and recalled in
Scheme 1.
Then, the experimental conditions of the condensation of 1 with hydrazines
were optimized. A detailed study was carried out using 3-chloro-4-tolylhydrazine.
It showed that both compounds reacted in a 1:2 molar ratio by heating in absolute
methanol to give the functionalized iminocoumarin 2 in one step in 85% yield
(Scheme 2).
It must be noted that when the reaction was conducted in a 1:1 molar ratio, the
same product was obtained but with a lower yield. Product 2 was isolated by simple
1
filtration with high purity as confirmed by the H NMR spectrum. The analytical
data agreed with the formula C29H28Cl2N6O2 in accordance with the structure of
2 established from Fourier transform infrared (FTIR) and NMR spectra. The FTIR
spectrum showed the disappearance of the original peaks at 2214 and 1724 cmꢀ1 aris-
ing from the CꢁN and COOEt functions, respectively, as well as the appearance of
absorption bands indicating the formation of the triazolonic heterocycle: NH (3200
Scheme 1.

890
M. KAMMOUN ET AL.
Scheme 2.
ꢀ1
and 3350 cmꢀ1), C N (1626 cm ), and C O (1709 cmꢀ1). These characteristic
=
=
absorptions are in accordance with the literꢀa1ture data related to triazolonic hetero-
ꢀ1
cycle (around 1640 cmꢀ1 for C N, 1705 cm for C O, and 3200 cm for NH),[33]
=
=
whereas absorption bands in pyrꢀim1 idines analogs previously described[28] appeared
at 1650 cmꢀ1 (C O) and 1570 cm (C N). The analysis of these spectroscopic data
indicates that condensation of iminocoumarin 1 with hydrazines gave selectively the
corresponding triazolonyl iminocoumarin, whereas reaction leading to benzopyra-
nopyrimidines did not take place (Scheme 3).
=
=
The structure of compound 2 was also confirmed by NMR spectroscopy. The
1H NMR spectrum showed the peaks arising from two chlorotolyl groups at 1.13
and 7.02–7.43 ppm, which indicates that two molecules of hydrazine have reacted.
1
The H NMR and two-dimensional (2D) correlation spectra showed the presence
of two resonances (9.46 and 12.10 ppm) related to NH, which were attributed by
comparison with analogous structures reported in the literature: the peak at
12.10 ppm corresponds to the NH function of the triazolonic heterocycle (literature:
11 ppm),[34] and the resonance at 9.46 ppm is due to the NH function of the substi-
tuted amino group (literature: 9.5 ppm).[22]
We show in Scheme 4 a possible mechanism involving several steps: (i) the
nucleophilic attack of hydrazine on the imidic function followed by the opening of
the pyrane ring, (ii) the Z=E isomerization of the amidine intermediate, (iii) cycliza-
tions to the iminocoumarin system and trizolonic heterocycle, and finally (iv) the
interaction between the hydrazinic fragment and the carbonyl group, leading to
the formation of the triazolonic heterocycle. The reaction does not stop at this stage
but goes further to 2-N-substituted imincoumarins.[19,22]
Hydrazine itself and five hydrazines provided with a phenyl group bearing up
to three substitutions behaved analogously when reacted with 1 under the same
Scheme 3.

NEW SERIES OF 3-TRIAZOLONYL IMINOCOUMARINS
891
Scheme 4.
conditions. They all afforded the corresponding N-substituted triazolonyl-
iminocoumarins (Scheme 2, Table 1). It can be noted that the reaction yield was
particularly good for the aromatic hydrazines.
In contrast, hydrazines whose phenyl group was highly substituted by fluorine
atoms reacted with 1 in a 1:1 molar ratio, leading to triazolonyl-iminocoumarins 9
and 10, respectively, without any substitution on the imidic nitrogen atom
(Scheme 5, Table 1). All attempts to obtain the corresponding N-substituted imino-
coumarins using a molar ratio of 1:2 were unsuccessful, whatever the experimental
conditions used.
Table 1. Synthesis of iminocoumarins 2–10
Compound
Time (h)
Yield (%)
Mp (ꢂC)
2
3
2
85
76
97
60
90
70
85
55
43
234
132
202
1.5
1.5
6
4
a
5
—
6
2
249
245
210
285
256
7
2
8
8
9b
10b
0.75
3.5
aDecomposition temperature ¼ 170 ꢂC.
bOnly N-unsubstituted compounds were obtained in all experiments.

892
M. KAMMOUN ET AL.
Scheme 5.
Optical Properties
Coumarins make up a well-known family of fluorescent compounds. Imino-
coumarins, which have almost the same aromatic system, also display interesting
optical properties.[35–39] This is the reason why we had a cursory glance at the spec-
troscopic behavior of our compounds. Except for compound 5, all the other com-
pounds bear at least one phenyl group, and it can be noticed that this group is
hardly involved in the electron conjugated system of the iminocoumarin structure.
Consequently, the substitution of the phenyl group in the hydrazine function should
have only a moderate influence upon the spectroscopic properties, via inductive or
steric effect, and it can be expected that these compounds display similar behavior.
Therefore, the optical properties were only measured on three of them, namely com-
pounds 2, 3, and 10. The results are gathered in Table 2. There were compared with
those previously reported for 3-cyano-7-diethylamino-iminocoumarin 10.[35,36]
Compounds 2, 3, and 10 were poorly soluble in organic solvents. However,
they could be studied in ethanol and dichloromethane at concentrations around
10ꢀ5 M for absorption and 10ꢀ6 M for fluorescence. In the visible spectrum, the
absorption spectrum of the three compounds displayed only one band peaking
around 450 nm, with an absorption tail extending until 560–580 nm. Therefore, the
Table 2. Maximum absorption wavelength (kabs), maximum excitation wavelength (kex), maximum
emission wavelength (kem), fluorescence lifetime (s), and fluorescence quantum yield (U) of compounds
2, 3, and 10 in EtOH and CH2Cl2 (the values given for 3-cyano-7-diethylamino-iminocoumarin 10 are from
Refs. 35 and 36; sh ¼ shoulder)
Compound
kabs (nm)
kex (nm)
kem (nm)
s (ns)
U
2 (EtOH)
2 (CH2Cl2)
3 (EtOH)
450
458
440
447
498
496
1.5 ꢃ 0.3
2.0 ꢃ 0.4
1.5 ꢃ 0.3
2.7 ꢃ 0.2
0.7 ꢃ 0.2
1.9 ꢃ 0.5
—
0.031 ꢃ 0.003
0.047 ꢃ 0.005
0.054 ꢃ 0.005
0.11 ꢃ 0.01
450
454
446
450
504
502
3 (CH2Cl2)
10 (EtOH)
10 (CH2Cl2)
10 (EtOH)
10 (CH2Cl2)
444
450
441
450
504
0.018 ꢃ 0.002
0.019 ꢃ 0.002
0.33 ꢃ 0.02
520 (sh 500)
468
460 (sh 482)
424
414 (sh 428)
—
414 (sh 429)
2.9 ꢃ 0.5
0.84 ꢃ 0.02

NEW SERIES OF 3-TRIAZOLONYL IMINOCOUMARINS
893
small structural differences between these compounds did not lead to significant
spectroscopic effect. In contrast, comparing the absorption spectra of compounds
10 and 10 showed that the substitution of the cyano group by a hetaryl cycle induced
a significant red shift of about 20 nm.
The three compounds were fluorescent. Normalized spectra in ethanol are
given in Fig. 1. In ethanol, the three compounds displayed similar excitation spectra,
as well as similar emission spectra, confirming that substitution on the imino group
hardly changes the spectroscopic characteristics. This was also the case in dichloro-
methane, except that the emission spectrum of 10 slightly differed from that of the
two other compounds (Table 2), a particularity that can be attributed to a specific
solvent effect.
The excitation spectrum had the same shape as the absorption spectrum, but in
most cases it was narrower and its maximum was slightly shifted to short wave-
lengths. This discrepancy suggests that despite careful filtration, the solutions still
contained a small amount of undissolved compounds. These aggregates are visible
on the red side of the absorption spectra but are not fluorescent. In fact, the exci-
tation spectra did not vary with the emission wavelength, and conversely, the emis-
sion spectra were independent of the excitation wavelength. This indicates the
presence of only one fluorescent species in each solution. The fluorescence quantum
yields of the three hetaryl-iminocoumarins were measured, but the values lack pre-
cision because of the presence of undissolved material that contributes to absorption
but not to fluorescence. Besides, an evolution of the fluorescence intensity with time
was noticed for compound 3 in ethanol. It can be attributed either to dissolution of
aggregates or to the decomposition of the compound toward a more fluorescent spe-
cies. However, the quantum yield values clearly indicate that the hetaryliminocou-
marins are much less fluorescent than 10, although all the lifetime values remained
in the nanosecond range, close to that of compound 10. Substituting the cyano group
by a triazolonyl group, which probably introduces n ! pꢄ transitions, is thus parti-
cularly unfavorable to fluorescence. Finally, it can be pointed out that compounds 2,
Figure 1. Normalized excitation and emission spectra of compounds 2 (dotted line), 3 (plain line), and 10
(broken line) in ethanol. For emission spectra, kex ¼ kabs max. For excitation spectra, kem is set at the
maximum intensity wavelength.

894
M. KAMMOUN ET AL.
3, and 10 were slightly more fluorescent in dichloromethane than in ethanol, a
behavior that has already been noticed for other iminocoumarins and is discussed
elsewhere.[35]
CONCLUSION
In marked contrast with the results obtained when amines or hydrazides of
carboxylic acids were used as nucleophilic reagents under similar conditions,[28,29]
the recyclization of 3-cyano-7-diethylamino-N-ethoxycarbonyl-iminocoumarin by
hydrazines did not lead to the expected benzopyranopyrimidines. In this case, the
reaction followed an original mechanism leading to the corresponding 3-triazolonyl-
iminocoumarins, substituted or not on the nitrogen atom of the imino group. The
compounds obtained displayed no attractive optical properties. However, this work
opens an interesting avenue for the synthesis of a new family of iminocoumarins that
might exhibit particular biological properties. Besides, our synthesis allowed the easy
introduction of an arylhalogenated group, borne by the triazolonyl group in the
3-position of the iminocoumarin heterocycle. The compounds thus obtained could
be interesting intermediates to prepare analogs of 3-arylhalogenated-coumarins,
knowing that many compounds of this series (for example, coumachlor)[30,31] have
proved to be particularly active as pesticides.
EXPERIMENTAL
Hydrazines were commercially available from Aldrich. 3-Cyano-N-ethoxycar-
bonyl-7-diethylamino-iminocoumarin 1 was prepared as previously described.[28]
Ethanol and dichloromethane (analytical grade) used for spectroscopic measure-
ments were from VWR Prolabo and SDS, respectively. The melting points were
determined on an Electrothermal 9100 apparatus. IR spectra were registered on a
Jasco FTIR 420 spectrophotometer apparatus using KBr pellets. 1H and 13C
NMR and CHcorr spectra were recorded on a Bruker WP 200 spectrometer operat-
ing at 300 and 75 MHz, respectively, in dimethylsulfoxide (DMSO-d6) with tetra-
methylsilane (TMS) as internal standard (chemical shifts in ppm). Elemental
microanalyses were preformed on a EA1112 analyser from CE Instruments at the
Service Commun de Microanalyses de l’ENCIACET. Ultraviolet (UV)=vis absorp-
tion spectra were recorded on a Hewlett-Packard 8452A diode array spectrophot-
ometer. Steady-state fluorescence work was performed on a Photon Technology
International (PTI) Quanta Master 1 spectrofluorometer. All excitation and emission
spectra were corrected. The fluorescence quantum yields (U) were determined using
the classical formula: U ¼ ðAsFxn2xUsÞ=ðAxFsns2Þ where A is the absorbance at the
excitation wavelength, F is the area under the fluorescence curve, and n is the refrac-
tive index. Subscripts s and x refer the standard and the sample of unknown quan-
tum yield, respectively. Coumarin 6 in ethanol (U ¼ 0.78) was taken as the
standard.[40] Fluorescence decay was measured with the stroboscopic technique using
a Strobe Master Fluorescence lifetime spectrophotometer from PTI. The excitation
source was a flash lamp filled with a mixture of nitrogen and helium (30=70). Data
were collected over 200 channels with a time base of 0.1 ns per channel. Analysis of
fluorescence decay was performed using the multiexponential method software from

NEW SERIES OF 3-TRIAZOLONYL IMINOCOUMARINS
895
PTI. All spectrophotometric measurements were conducted in a thermostated cell at
25 ꢂC. For spectroscopic work, compounds 2, 3, and 10 were purified by thin-layer
chromatography (TLC) on silica plate using chloroform as the eluent. The solutions
were carefully filtrated on paper filter before use.
General Procedure for the Synthesis of N-Substituted 3-Triazolonyl
Iminocoumarins 2–8
A solution of 3-cyano-N-ethoxycarbonyl-7-diethylamino-iminocoumarin 1
(5 mmol) and hydrazine (10 mmol) in 30 ml of absolute methanol was refluxed
during the time indicated in Table 1. After complete reaction, the N-substituted
3-hetaryl iminocoumarin obtained was separated by filtration and washed with
methanol.
General Procedure for the Synthesis of 3-Hetaryl-iminocoumarins
9–10
A solution of 3-cyano-N-ethoxycarbonyl-7-diethylamino-iminocoumarin 1
(5 mmol) and hydrazine (5 mmol) in 30 ml of absolute methanol was refluxed during
the time indicated in Table 1. After complete reaction, the simple 3-hetaryl imino-
coumarin obtained was separated by filtration and washed with methanol.
Data
3-[1-(3-Chloro-4-tolyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-yl]-2-N-[3-
chloro-4-tolylamino]-2-imino[2H]coumarin (2). Orange-brown solid, IR (cmꢀ1):
1
=
=
=
n ¼ 1577 (C C), 1626 (C N), 1709 (C O), 3200 and 3350 (NH). H NMR: d ¼ 1.13
(t, J ¼ 6.9 Hz, 6H, CH3), d ¼ 2.19 (s, 3H, CH3), d ¼ 2.32 (s, 3H, CH3), 3.41 (q,
J ¼ 6.9 Hz, 4H, CH2N), 6.50 (d, J5,6 ¼ 9.0, 1H, H6), 6.53 (s, 1H, H8), 7.02 (d,
J ¼ 8.1 Hz, 1H, HAr), 7.12 (d, J ¼ 8.1 Hz, 1H, HAr), 7.23 (d, J ¼ 8.1 Hz, 2H,
HAr), 7.42 (d, J ¼ 8.1 Hz, 2H, HAr), 7.87 (d, J5,6 ¼ 9.0 Hz, 1H, H5), 8.08 (s, 1H,
H4), 9.46 (s, 1H, NH), 12.10 (s, 1H, NH). 13C NMR: d ¼ 12.82 (2CH3), 19.01
(CH3-Ar), 19.38 (CH3-Ar), 44.43 (2CH2N), 97.00 (C6), 107.53 (C10), 107.89 (C3),
109.59 (C8), 111.74 (CH-Ar), 112.79 (CH-Ar), 116.54 (C5), 117.90 (C4), 124.29 (C-
CH3(Ar)), 129.87 (CH-Ar), 130.30 (CH-Ar), 131.56 (CH-Ar), 131.90 (C-CH3(Ar)),
131.91 (CH-Ar), 133.76 (C-Cl), 133.82 (C-Cl), 137.18 (C-N (Ar)), 138.16 (C-N
=
(Ar)), 140.76 (C7), 142.84 (C-Ar), 145.31 (NH-C N), 150.47 (C9), 152.43 (C2),
=
154.77 (C O). Calculated for C29H28Cl2N6O2: C, 61.81; H, 5.01; N, 14.91%. Found:
C, 61.46; H, 5.33; N, 14.35%.
3-[1-(4-Bromophenyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-yl]-2-N-[4-
bromophenylamino]-2-imino[2H]coumarin (3). Orange-brown solid, IR (cmꢀ1):
1
=
=
=
n ¼ 1587 (C C), 1622 (C N), 1713 (C O), 3271 and 3368 (NH). H NMR: d ¼ 1.13
(t, J ¼ 6.9 Hz, 6H, CH3), 3.39 (q, J ¼ 6.9 Hz, 4H, CH2N), 6.49 (dd, J5,6 ¼ 8.4,
J6,8 ¼ 1.8 Hz, 1H, H6), 6.53 (d, J6,8 ¼ 1.8 Hz, 1H, H8), 7.11 (d, J ¼ 8.7 Hz, 2H,
HAr), 7.33 (d, J ¼ 8.7 Hz, 2H, HAr), 7.66 (d, J ¼ 8.7 Hz, 2H, HAr), 7.95 (d,
J ¼ 8.7 Hz, 2H, HAr), 7.25 (d, J5,6 ¼ 8.4 Hz, 1H, H5), 7.41 (s, 1H, H4), 8.30 (s, 1H,

896
M. KAMMOUN ET AL.
NH), 9.53 (s, 1H, NH). 13C NMR: d ¼ 11.55 (2CH3), 43.17 (2CH2N), 95.77 (C8),
106.26 (C10), 106.66 (C6), 108.12 (C3), 108.47 (C-Br), 113.50 (CH-Ar), 115.94
(C-Br), 118.69 (CH-Ar), 128.64 (C5), 129.19 (C4), 130.44 (CH-Ar), 130.99 (CH-Ar),
=
136.16 (C-N (Ar)), 137.26 (C-N (Ar)), 141.76 (C7), 143.87 (NH-C N), 149.21 (C2),
=
151.17 (C9), 153.54 (C O). Calculated for C27H24Br2N6O2: C, 51.94; H, 3.87; N,
13.46%. Found: C, 52.26; H, 3.49; N, 13.66%.
3-[1-(2,3-Dimethylphenyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-yl]-2-
N-[2,3-dimethylphenylamino]-2-imino[2H]coumarin (4). Orange-brown solid,
1
IR (cmꢀ1): n ¼ 1572 (C C), 1619 (C N), 1722 (C O), 3289 and 3308 (NH). H
NMR: d ¼ 1.23 (t, J ¼ 7.0 Hz, 6H, CH3), d ¼ 2.33 (s, 6H, CH3), d ¼ 2.35 (s, 6H,
CH3), 3.43 (q, J ¼ 7.0 Hz, 4H, CH2N), 6.36 (d, J6,8 ¼ 2.1 Hz, 1H, H8), 6.44 (dd,
J5,6 ¼ 8.7, J6,8 ¼ 2.1 Hz, 1H, H6), 7.11 (d, J5,6 ¼ 8.7 Hz, 1H, H5), 7.15–7.30 (m, 6 H,
HAr), 7.65 (s, 1H, NH), 7.70 (s, 1H, H4), 10.30 (s, 1H, NH). 13C NMR: d ¼ 12.96
(2CH3), 15.00 (CH3Ar), 20.78 (CH3Ar), 20.89 (CH3Ar), 31.33 (CH3Ar), 45.10
(2CH2N), 97.27 (C8), 108.35 (C10), 108.48 (C3), 108.66 (C6), 111.21 (C5), 120.24
(CAr), 122.44 (CH-Ar), 125.63 (CH-Ar), 126.51 (CH-Ar), 127.24 (CH-Ar), 128.25
(C4), 129.88 (CH-Ar), 130.85 (CH-Ar), 134.79 (CAr), 135.82 (CAr), 137.31 (CAr),
=
=
=
=
138.76 (C-N (Ar)), 141.21 (C-N (Ar)), 141.79 (C7), 142.74 (NH-C N), 150.79
=
(C2), 152.91 (C9), 154.91 (C O). Calculated for C31H34N6O2: C, 71.24; H, 6.56;
N, 16.08. Found: C, 71.48; H, 6.37; N, 16.33.
3-(5-Oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-yl)-2-N-amino-2-imino[2H]-
coumarin (5). Red solid, IR (cmꢀ1): n ¼ 1606 (C C), 1647 (C N), 1688 (C O),
3300 and 3350 (NH). 1H NMR: d ¼ 1.09 (t, J ¼ 6.9 Hz, 6H, CH3), 3.35 (q, J ¼ 6.9 Hz,
4H, CH2N), 5.71 (s, 2H, NH2), 6.40 (d, J5,6 ¼ 8.7 Hz, 1H, H6), 6.42 (s, 1H, H8), 7.17
=
=
=
(d, J5,6 ¼ 8.7 Hz, 1H, H5), 7.23 (s, 1H, H4), 10.87 (s, 1H, NH), 11.55 (s, 1H, NH). 13
C
NMR: d ¼ 12.94 (2CH3), 44.46 (2CH2N), 97.29 (C6), 107.55 (C8), 107.71 (C10),
=
111.10 (C3), 127.00 (C4), 129.61 (C5), 140.04 (C7), 142.71 (NH-C N), 150.09 (C2),
=
154.87 (C9), 155.65 (C O). Calculated for C15H18N6O2: C, 57.31; H, 5.77; N,
26.74. Found: C, 57.40; H, 5.88; N, 26.42.
3-[1-(2-Fluorophenyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-yl]-2-N-[2-
fluorophenylamino]-2-imino[2H]coumarin (6). Red-brown solid, IR (cmꢀ1):
n ¼ 1580 (C C), 1608 (C N), 1708 (C O), 3326 and 3350 (NH). 1H NMR:
d ¼ 1.16 (t, J ¼ 6.9 Hz, 6H, CH3), 3.44 (q, J ¼ 6.9 Hz, 4H, CH2N), 6.50 (dd,
J5,6 ¼ 8.7, J6,8 ¼ 1.8 Hz, 1H, H6), 6.66 (d, J6,8 ¼ 1.8 Hz, 1H, H8), 6.70–6.85 (m, 2H,
HAr), 7.02–7.20 (m, 4H, HAr), 7.40–7.50 (m, 2H, HAr), 7.28 (d, J5,6 ¼ 8.7, 1H,
H5), 8.43 (s, 1H, H4), 8.80 (s, 1H, NH), 9.84 (s, 1H, NH). 13C NMR: d ¼ 12.89
(2CH3), 46.05 (2CH2N), 97.45 (2CHAr), 98.14 (C8), 105.85 (C6), 108.02 (C10),
108.66 (C3), 114.70 (CHAr), 116.98 (CHAr), 117.2 (2CHAr), 121.50 (2CHAr),
126.00 (CHAr), 126.04 (CHAr), 129.78 (C-N(Ar)), 132.75 (C5), 134.01 (C4), 134.44
=
=
=
=
(C-N(Ar)), 144.74(C7), 145.34 (C-F), 146.11 (NH-C N), 149.65 (C-F), 153.72
=
(C2), 154.65 (C9), 157.89 (C O). Calculated for C27H24F2N6O2: C, 64.53; H, 4.81;
N, 16.72%. Found: C, 64.49; H, 4.66; N, 16.75.
3-[1-(2,4-Difluorophenyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-yl]-2-N-
[difluorophenylamino]-2-imino[2H]coumarin (7). Red-brown solid, IR (cmꢀ1):
n ¼ 1587 (C C), 1618 (C N), 1711 (C O), 3232 and 3312 (NH). 1H NMR:
=
=
=

NEW SERIES OF 3-TRIAZOLONYL IMINOCOUMARINS
897
d ¼ 1.14 (t, J ¼ 6.9 Hz, 6H, CH3), 3.48 (q, J ¼ 6.9 Hz, 4H, CH2N), 6.49 (dd,
J5,6 ¼ 9 Hz, J6,8 ¼ 1.8 Hz, 1H, H6), 6.61 (d, J6,8 ¼ 1.8 Hz, 1H, H8), 6.90–7.01 (m,
2H, HAr), 7.14–7.27 (m, 2H, HAr), 7.32–7.46 (m, 2H, HAr), 7.49 (d, J5,6 ¼ 9 Hz,
1H, H5), 8.39 (s, 1H, H4), 8.72 (s, 1H, NH), 9.70 (s, 1H, NH). 13C NMR:
d ¼ 12.76 (2CH3), 44.84 (2CH2N), 96.87 (C8), 97.45 (2CHAr), 107.35 (C6), 107.97
(C10), 108.36 (C3), 110.70 (2CHAr), 118.71 (CHAr), 118.73 (CHAr), 129.23
(C-N(Ar)), 129.77 (C-N(Ar)), 131.70 (C5), 133.13 (C4), 144.55 (C7), 145.59
=
(NH-C N), 149.73 (C-F), 152.33 (C-F), 153.57 (C-F), 153.60 (C-F), 153.64 (C2),
=
154.33 (C9), 157.86 (C O). Calculated for C27H22F4N6O2: C, 60.22; H, 4.12; N,
15.61. Found: C, 60.56; H, 4.13; N, 15.55%.
3-[1-(2,4,6-Trichlorophenyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-yl]-
2-N-[2,4,6-trichlorophenylamino]-2-imino[2H]coumarin (8). Red-brown solid,
1
IR (cmꢀ1): n ¼ 1587 (C C), 1618 (C N), 1711 (C O), 3232 and 3312 (NH). H
NMR: d ¼ 1.14 (t, J ¼ 6.9 Hz, 6H, CH3), 3.41 (q, J ¼ 6.9 Hz, 4H, CH2N), 6.49 (dd,
J5,6 ¼ 9 Hz, J6,8 ¼ 1.8 Hz, 1H, H6), 6.64 (d, J6,8 ¼ 1.8 Hz, 1H, H8), 7.33 (d,
J5,6 ¼ 9 Hz, 1H, H5), 7.59 (s, 1H, H4), 7.65 (s, 2H, HAr), 7.94 (s, 2H, HAr), 8.28
(s, 1H, NH), 11.19 (s, 1H, NH). 13C NMR: d ¼ 14.61 (CH3), 14.80 (CH3), 46.39
(2CH2N), 99.20 (C8), 109.19 (C6), 110.07 (C10), 115.81 (C3), 119.65 (C-Cl), 128.71
(C-Cl), 128.89 (C-Cl), 131.17 (2CH-Ar), 131.31 (2CH-Ar), 132.36 (C5), 133.34
(C4), 138.04 (C-Cl), 138.11 (C-Cl), 140.27 (C-Cl), 145.56 (C-N(Ar)), 152.80
=
=
=
=
(C-N(Ar)), 154.41 (C7), 156.63 (NH-C N), 160.40 (C2), 160.89 (C9), 161.38
=
(C O). Calculated for C27H20Cl6N6O2: C, 49.17; H, 2.99; N, 12.48. Found: C,
49.18; H, 2.93; N, 12.51.
3-[1-(2,3,5,6-Tetrafluorophenyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-3-
=
yl]-2-imino[2H]coumarin (9). Red-brown solid, IR (cmꢀ1): n ¼ 1602 (C C), 1653
1
=
=
(C N), 1737 (C O), 3303 and 3372 (NH). H NMR: d ¼ 1.35 (t, J ¼ 6.9 Hz, 6H,
CH3), 3.65 (q, J ¼ 6.9 Hz, 4H, CH2N), 6.80 (dd, J5,6 ¼ 6.9, J6,8 ¼ 1.5 Hz, 1H, H6),
6.92 (d, J6,8 ¼ 1.5 Hz, 1H, H8), 7.36 (s, 1H, HAr), 7.60 (d, J5,6 ¼ 6.9 Hz, 1H, H5),
7.94 (s, 1H, H4), 8.27 (s, 1H, NH), 9.33 (s, 1H, NH). 13C NMR: d ¼ 13.44 (2CH3),
45.56 (2CH2N), 96.05 (CHAr), 97.05 (C8), 105.33 (C6), 106.98 (C10), 109.07 (C3),
120.15 (C-N(Ar)), 128.89 (2C-F), 130.54 (C5), 131.44 (C4), 143.56 (C7), 144.22
=
(NH-C N), 147.77 (2C-F), 151.53 (C2), 152.53 (C9), 155.13 (C O). Calculated for
=
C21H17F4N5O2: C, 56.38; H, 3.83; N, 15.65. Found: C, 56.49; H, 3.73; N, 15.45.
3-[1-(2,3,4,5,6-Pentafluoro-phenyl)-5-oxo-2,5-dihydro-[1H]-[1,2,4]triazol-
=
3-yl]-2-imino[2H]coumarin (10). Red-brown solid, IR (cmꢀ1): n ¼ 1607 (C C),
1
=
=
1646 (C N), 1745 (C O), 3354 and 3390 (NH). H NMR: d ¼ 1.35 (t, J ¼ 6.9 Hz,
6H, CH3), 3.67 (q, J ¼ 6.9 Hz, 4H, CH2N), 6.82 (dd, J5,6 ¼ 6.9 Hz, J6,8 ¼ 1.5 Hz,
1H, H6), 6.87 (d, J6,8 ¼ 1.5 Hz, 1H, H8), 7.62 (d, J5,6 ¼ 6.9 Hz, 1H, H5), 7.93 (s,
1H, H4), 9.26 (s, 1H, NH), 11.60 (s, 1H, NH). 13C NMR: d ¼ 12.64 (2CH3), 44.97
(2CH2N), 96.95 (C8), 106.25 (C6), 107.32 (C10), 108.76 (C3), 116.10 (C-N(Ar)),
129.99 (C-F), 130.19 (C5), 130.60 (C4), 133.59 (2C-F), 136.89 (2C-F), 142.57 (C7),
=
=
143.54 (NH-C N), 151.22 (C2), 152.04 (C9), 154.49 (C O). Calculated for
C21H16F5N5O2: C, 54.20; H, 3.47; N, 15.05. Found: C, 54.26; H, 3.33; N, 14.85.

898
M. KAMMOUN ET AL.
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