A short route to [1,2,3]-triazolyl coumarin and quinolone derivatives by Cu(I) catalyzed 1,3-dipolar cycloaddition and fluorescence studies

Article abstract of DOI:10.2174/157017809787003250

Hitherto unreported [1,2,3]-triazolyl coumarin and quinolone derivatives in good to excellent yields have been expediently synthesized from 6- and 7-azidocoumarin and 6-azidoquinolone by copper (I) catalyzed 1,3-dipolar cycloaddition. Azidocoumarins and a

Full text of DOI:10.2174/157017809787003250

82
Letters in Organic Chemistry, 2009, 6, 82-87
A Short Route to [1,2,3]-Triazolyl Coumarin and Quinolone Derivatives by
Cu(I) Catalyzed 1,3-Dipolar Cycloaddition and Fluorescence Studies
Krishna C. Majumdar* and Shovan Mondal
Department of Chemistry, University of Kalyani, Kalyani-741235, W.B. India
Received July 13, 2008: Revised October 18, 2008: Accepted November 07, 2008
Abstract: Hitherto unreported [1,2,3]-triazolyl coumarin and quinolone derivatives in good to excellent yields have been
expediently synthesized from 6- and 7-azidocoumarin and 6-azidoquinolone by copper (I) catalyzed 1,3-dipolar cycload-
dition. Azidocoumarins and azidoquinolones were in turn prepared efficiently from the corresponding amines. Fluores-
cence studies of the newly synthesized [1,2,3]- triazolyl coumarin and quinolone derivatives are also described.
Keywords: 1,3-dipolar cycloaddition, 6 and 7-azidocoumarin, 6-azidoquinolone, [1,2,3] triazole, phenyl acetylene, fluores-
cence.
Nitrogen heterocycles are widely distributed in nature,
including amino acids, purines, pyrimidines etc. Heterocyc-
lic compounds such as [1,2,3]-triazoles exhibit biological
activities including anti-HIV activity, [1] anti-microbial ac-
tivity against Gram positive bacteria, [2] selective ꢀ3 adren-
ergic receptor agonism [3]. [1,2,3]-triazoles have also found
wide use in industrial applications as dyes, corrosion inhibi-
tors, photo stabilizers, photographic materials and agro-
chemicals [4]. Based on the application potential of the
[1,2,3]-triazole moiety, many fluorescent libraries have been
developed by Cu(I)- catalyzed Huisgen 1,3-dipolar cycload-
of coumarin and quinolone containing triazolyl derivatives
with diversity at the 6- and 7- positions via Huisgen cy-
cloaddition reaction. Herein we report our results.
The required precursors 2(a-c) were prepared by diazoti-
zation of 1(a-c) in tetrafluoroboric acid (40% solution in
water) with dropwise addition of sodium nitrite (solution in
water) at 0 to -5 ˚C and stirring for 1 h. Sodium azide was
added to the methanolic solution of the diazotized salt and
stirred for 1 h at rt to give azido derivatives (2a-c) in 70-75%
yields (Scheme 1).
R
R
5
4
6
(i) HBF4, NaNO2, water, 0 ˚C, 30 mins
(ii) NaN3, MeOH, 1h
3
H2N
N3
7
X
O
X
O
8
2 (a-c)
1 (a-c)
2a, 6-NH2, X = O, R = H, 75%
2b, 7-NH2, X = O, R = CH3, 72%
2c, 6-NH2, X = NMe, R = H, 70%
1a, 6-NH2, X = O, R = H
1b, 7-NH2, X = O, R = CH3
1c, 6-NH2, X = NMe, R = H
Scheme 1. Synthetic procedure of azido-coumarin and quinolone.
dition of azides and alkynes. Chang et al. recently, devel-
oped libraries of styryl dyes bearing DNA-sensitive fluores-
cent sensors [5] and ꢀ-amyloid sensors [6]. Subsequently,
Bauerle et al. [7] and Wang et al. [8] reported coumarin li-
braries with diversity at the 3-position via Suzuki-Miyaura,
Heck, Sonogashira-Hagihara or Husigen cycloaddition reac-
tions. The compounds containing coumarin moiety showed
interesting photo-physical property such as fluorescence.
Therefore, in continuation to our longstanding interest in
coumarin and quinolone chemistry, [9-11] we became inter-
ested to develop an efficient method for the synthesis
The 4-chloro phenyl acetylene (B) and 4-nitro phenyl
acetylene (C) were prepared from their corresponding alde-
hydes by portion wise addition of triphenyl phosphine to a
solution of the aldehyde and carbon tetrabromide in anhy-
drous dichloromethane at 0 ˚C followed by stirring at rt for 1
h. The dibromoalkene was then treated with n-BuLi in anhy-
drous THF at –78 ˚C to give B and C. (Scheme 2).
The final triazolyl derivatives of coumarin and quinolone
(3a-h) were obtained in 68-80% yields by stirring azides 2a-
c (4.99 mmol) and alkynes A-C (5.99 mmol) in the presence
of a catalytic amount (10 mol%) of CuI in DMSO at 60˚C
for 1 h (Scheme 3).
Recently, Wang et al. [8] have reported a coumarin li-
brary at the 3-position by [1,2,3]-triazole synthesis using
CuSO4 and sodium ascorbate and their protocol takes 12 to
*Address correspondence to this author at the Department of Chemistry,
University of Kalyani, Kalyani 741235, west Bengal, India; Tel: +91-33-
2582-7521; Fax: +91-33-25828282; E-mail: kcm_ku@yahoo.co.in
1570-1786/09 $55.00+.00
© 2009 Bentham Science Publishers Ltd.

A Short Route to [1,2,3]-Triazolyl Coumarins and Quinolones
Letters in Organic Chemistry, 2009, Vol. 6, No. 1
83
Br
Br
CHO
CBr4, dry CH2Cl2, Ph3P
n-BuLi, dry THF, -78 ˚C,
0 ˚C, N2-atm, 1hr
N2-atm, 1 hr
R
R
R
(R = Cl, NO2)
(R = Cl, NO2)
B, C
B, R = Cl
C, R = NO2
Scheme 2. Synthetic procedure of alkynes.
R
R'
R
X
"click chemistry"
N3
+
10 mol% CuI (I), DMSO,
60 ˚C, 1 h
X
O
N
N
N
R'
O
2a-c
A-C
3a-h
Scheme 3. Synthesis of [1,2,3] triazol compound.
24 h for the reaction, a lengthy method, unsuitable for con-
struction of a library. Very recently Bertounesque and co-
workers have reported triazinyl-triazole phosphate [12] using
CuSO4 and ascorbic acid and their protocol also took 24 h
for completion of the reaction. Very recently Ackermann et
al. also reported the synthesis of triazolyl derivatives by
click reaction [13] using sodium azide. As a part of the
study, we have conducted a series of experiments with the
substrate 2a where sequential changes were made to the cata-
lyst, solvent and temperature for optimization of the reaction
condition (Table 1). Excellent result was obtained by heating
the azide and the alkyne in DMSO at 60˚C. This optimized
condition was applied to other substrates for the synthesis of
triazole derivatives.
Photo Physical Properties of [1,2,3]-Triazole Coumarin
and Quinolone Derivatives
Coumarin and quinolone are unambiguous core moieties
for the fluorogenic probes. We have utilized these moieties
since they are small in size, biocompatible and easy to ma-
nipulate synthetically. In particular, coumarins are important
because of their pharmacological activity [14] and photo-
physical properties and they have been extensively applied
as laser dyes [15]. Substitution at the 3-, 6- and 7- positions
of coumarin dyes are known to have a strong impact on their
fluorescence properties [7, 16, 17]. Therefore we have stud-
ied the photo physical properties of the newly synthesized
[1,2,3]-triazole coumarin and quinolone derivatives. A 0.5 X
10-6 M concentration of coumarin and quinolone derivatives
(3a-h) in DMSO was used for photo physical property stud-
ies. The photoluminescence spectra of the compounds (3a-h)
are shown in Fig. (1).
Isolation of the products is simple and straightforward as
the solids precipitated after pouring the reaction mixture into
water could be obtained by filtration. Simple recrystalliza-
tion from ethanol gave the pure products. The results for all
the new compounds are depicted in Table 2.
The fluorescence intensities of these compounds 3 (a-h)
in acetonitrile, methanol and DMSO were measured (Table
Table 1. Optimized Conditions for 3a
Entry
Solvent
Catalyst
Temperature
Time (h)
Yielda(%)
1
2
3
4
5
Ethanol/H2O (1 : 1)
DMSO/H2O (1 :1)
Ethanol
5% CuSO4 + 10% NaAsc
5% CuSO4 + 10% NaAsc
10 mol% CuI
rt
rt
12
12
5
63
65
65
67
80
rt
DMSO
10 mol% CuI
rt
5
DMSO
10 mol% CuI
60 ˚C
1
aIsolated yield after recrystallisation from ethanol.

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Letters in Organic Chemistry, 2009, Vol. 6, No. 1
Majumdar and Mondal
Table 2. Triazolyl-Coumarins and Quinolones
Entry
Azide
Alkyne
Product
Yield (%)
N3
N
N
1
80
N
O
O
O
O
A
2a
2a
2a
3a
N3
N
N
Cl
Cl
2
3
82
N
O
O
O
O
B
3b
N3
N
O2N
NO2
N
72
N
O
O
O
O
C
3c
4
5
78
N
O
O
N3
O
O
A
N
N
2b
3d
Cl
73
Cl
N
O
O
N3
O
O
B
N
N
2b
3e
N3
N
6
7
8
81
N
N
N
O
N
O
2c
A
3f
N3
N
Cl
Cl
N
79
N
N
O
N
O
B
2c
3g
N3
N
O2N
NO2
N
68
N
N
O
N
O
C
2c
3h
3). Compound 3 (a-c) gave no absorption bands and com-
pound 3 (d-e) gave hump in methanol due to insolubility and
very low solubility of these compounds respectively.
In conclusion, we have demonstrated a simple and short
route to [1,2,3]-triazolyl coumarin and quinolone derivatives.
This protocol offers several advantages such as all the reac-
tions were completed within one hour without any undesired
side products. Good yields of the products are obtained
which do not need extensive purification, makes it an useful
and attractive process for the construction of libraries of
coumarin and quinolone possessing diversity at 6 and 7 posi-
tions by [1,2,3]-triazolyl synthesis.Coumarin and quinolone
derivatives show good photo physical effects and have a
stable fluorescence property.
Interestingly compounds 2a-c showed no fluorescence
property due to the quenching effect from electron-rich ꢀ-
nitrogen of the azide group and the compounds 3a-h exhib-
ited high fluorescence due to elimination of the quenching
through the formation of the triazole ring. The detailed
mechanistic investigations, such as measurements by single
wavelength excitation, time-resolved measurement of fluo-
rescence decays, and lifetimes, are in progress.

A Short Route to [1,2,3]-Triazolyl Coumarins and Quinolones
Letters in Organic Chemistry, 2009, Vol. 6, No. 1
85
Fig. (1). Fluorescence spectra of triazolyl-coumarin and quinolone dyes. Each compound were measured in 0.5 X 10-6 M solution in DMSO.
Table 3. Fluorescence Intensity of Triazolyl-Coumarin and Quinolone Dyes
Compound
DMSO
CH3CNa
Peak (nm)
CH3OHa
UV (nm) (in DMSO)
Peak (nm)
Intensity
Intensity
Peak (nm)
Intensity
3a
3b
3c
3d
3e
3f
565
562
560
557
548
571
561
554
5581
8607
566
531
531
548
543
570
554
542
16166
8793
-
-
-
895, 263, 204
890, 266, 217
895, 888, 321
861, 326, 284
861, 491, 326
891, 456, 344
895, 457, 338
883, 332, 260
-
13435
14470
24492
14707
41945
43595
11529
14090
16122
16302
30611
48552
-
-
576(h)
576 (h)
574
556
546
21452
21583
17118
31294
33260
3g
3h
aContaining 0.5% DMSO as cosolvent, h = hump.
EXPERIMENTAL SECTION
General
BIN YVON luminescence spectrometer). Silica gel (60-120
mesh) was used for chromatographic separation. Silica gel-G
[E-Mark (India)] was used for TLC. Petroleum-ether refers
to the fraction between 60 and 80 ˚C.
Melting points were determined in open capillaries and
are uncorrected. IR spectra were run on KBr pellets on a
Perkin-Elmer 120-000A apparatus (ꢀ
NMR spectra were determined for solutions in CDCl3 with
TMS as internal standard on a Bruker DPX-400. 13C-NMR
spectra were determined for solutions in CDCl3 on a Bruker
DPX-125. The photoluminescence experiments of the com-
pounds were performed on a Fluoro Max-3 (HORIBA JO-
1
in cm-1) and H-
max
General Procedure for the Synthesis of Azido-Coumarins
and Quinolone
To a magnetically well-stirred mixture of the amines 1a-c
(12.41 mmol) in tetrafluoroboric acid (40% solution in wa-
ter, 6.8 mL), a solution of NaNO2 (1.28g, 18.6 mmol) in wa-

86
Letters in Organic Chemistry, 2009, Vol. 6, No. 1
Majumdar and Mondal
ter (2 mL) was added drop wise at 0 to -5 ˚C and stirring was
continued for 1 h. The solid diazonium salt was filtered and
dried. The solid salt was then taken in dry MeOH (10 mL)
and sodium azide (0.887g, 13.7 mmol) was added all at once
at ice cool condition. After stirring for 1 h at rt, the solvent
was removed in vacuo and the residue was extracted with
Et2O (3 X 30 mL) and the ether extract was washed with
water (20 mL). The ether extract was dried (Na2SO4) and
concentrated to afford the desired products 2a-c in 70-75%
yield.
60 ˚C. After cooling, the reaction mixture was poured into
water (100 mL). The solid was filtered and crystallized from
ethanol (100 mL) to give the desired products.
6-(4-phenyl-1H-1,2,3-triazol-1-yl)-2H-chromen-2-one (3a)
Green solid, mp above 260˚C, yield 80%. IR (KBr, cm-1)
1
ꢀ
max: 1735; H-NMR (CDCl3, 400 MHz) ꢁ: 6.65 (d, 1H, J =
9.7 Hz), 7.41 (d, 1H, J = 6.1 Hz), 7.50 (d, 2H, J = 7.1 Hz),
7.68 (d, 1H, J = 8.3 Hz), 7.95 (d, 2H, J = 7.0 Hz), 8.18 (t,
2H, J = 9.8 Hz), 8.39 (s, 1H); 13C-NMR (CDCl3, 125 MHz)
ꢁ: 117.6, 117.8, 119.4, 119.5, 119.7, 123.4, 125.2, 128.2,
128.7, 128.9, 129.9, 132.2, 132.7, 143.4, 147.3, 152.8, 159.3;
LCMS: m/z [M + H]+ 290.2. Anal. Calcd. for C17H11N3O2 :
C, 70.58; H, 3.83; N, 14.53 %. Found: C, 70.74; H, 3.68; N,
14.66 %.
6-azido-2H-chromen-2-one (2a)
White solid, mp 158-160 ˚C, yield 75%. IR (KBr, cm-1)
1
ꢀ
max: 2108, 1713; H-NMR (CDCl3, 400 MHz) ꢁ: 6.56 (d,
1H, J = 9.6 Hz), 7.34 (dd, 1H, J = 8.4, 1.6 Hz), 7.44 (d, 1H, J
= 8.8 Hz), 7.58 (d, 1H, J = 1.8 Hz), 8.05 (d, 1H, J = 9.5 Hz);
LCMS: m/z [M + H]+ 188.2. Anal. Calcd. for C9H5N3O2 : C,
57.76; H, 2.69; N, 22.45 %. Found: C, 57.85; H, 2.74; N,
22.54 %.
6-(4-(4-chlorophenyl)-1H-1,2,3-triazol-1-yl)-2H-chromen-
2-one (3b)
Yellow solid, mp above 230˚C, yield 82%. IR (KBr, cm-
1) ꢀmax: 1725; H-NMR (CDCl3, 400 MHz) ꢁ: 6.65 (d, 1H, J
1
7-azido-4-methyl-2H-chromen-2-one (2b)
= 9.6 Hz), 7.59 (d, 2H, J = 8.5 Hz), 7.69 (d, 1H, J = 9.0 Hz),
7.96 (d, 2H, J = 8.5 Hz), 8.15 (dd, 1H, J = 8.9, 2.5 Hz), 8.19
(d, 1H, J = 9.7 Hz), 8.37 (d, 1H, J = 2.5 Hz); LCMS: m/z [M
+ H]+ 324.3. Anal. Calcd. for C17H1˚ClN3O2 : C, 63.07; H,
3.11; N, 12.98 %. Found: C, 62.88; H, 3.12; N, 12.90 %.
White solid, mp 100-102 ˚C, yield 72%. IR (KBr, cm-1)
1
ꢀ
max: 2118, 1722; H-NMR (CDCl3, 400 MHz) ꢁ: 2.41 (s,
3H), 6.33 (s, 1H), 7.12 (d, 1H, J = 8.5 Hz), 7.15 (s, 1H), 7.77
(d, 1H, J = 8.4 Hz); LCMS: m/z [M + H]+ 202.3. Anal.
Calcd. for C10H7N3O2: C, 59.70; H, 3.51; N, 20.89 %. Found:
C, 59.84; H, 3.63; N, 20.82 %.
6-(4-(4-nitrophenyl)-1H-1,2,3-triazol-1-yl)-2H-chromen-2-
one (3c)
6-azido-1-methylquinoline-2-(1H)-one (2c)
Yellow solid, mp 180-182˚C, yield 72%. IR (KBr, cm-1)
max: 1729, 1343; H-NMR (CDCl3, 400 MHz) ꢁ: 6.66 (d,
1H, J = 9.6 Hz), 7.70 (d, 1H, J = 8.8 Hz), 8.01 (dd, 1H, J =
8.4, 1.6 Hz), 8.10 (dd, 1H, J = 8.5, 1.7 Hz), 8.15 (d, 1H, J =
8.6 Hz), 8.17 - 8.22 (m, 2H), 8.39-8.41 (m, 2H), 9.6 (d, 1H, J
= 9.6 Hz); LCMS: m/z [M + H]+ 335.1. Anal. Calcd. for
C17H10N4O4 : C, 61.08; H, 3.02; N, 16.76 %. Found: C, 61.2;
H, 3.2; N, 16.86 %.
Off-white solid, mp 80-82 ˚C, yield 70%. IR (KBr, cm-1)
ꢀ
1
1
ꢀ
max: 2098, 1651; H-NMR (CDCl3, 400 MHz) ꢁ: 3.58 (s,
3H), 6.64 (d, 1H, J = 9.5 Hz), 7.34 (dd, 1H, J = 8.9, 2.3 Hz),
7.52 (d, 1H, J = 2.5 Hz), 7.54 (d, 1H, J = 9.1 Hz), 7.88 (d,
1H, J = 9.5 Hz); LCMS: m/z [M + H]+ 201.3. Anal. Calcd.
for C10H8N4O : C, 59.99; H, 4.03; N, 27.99 %. Found: C,
59.91; H, 4.11; N, 27.92 %.
4-methyl-7-(4-phenyl-1H-1,2,3-triazol-1-yl)-2H-chromen-
2-one (3d)
General Procedure for the Synthesis of Alkynes from
Aldehydes
Yellow solid, mp above 230˚C, yield 78%. IR (KBr, cm-
1) ꢀmax: 1712, 1622; H-NMR (CDCl3, 400 MHz) ꢁ: 3.38 (s,
1
To a well-stirred solution of aldehyde (11.5 mmol) and
CBr4 (5.74g, 17.25 mmol) in dry CH2Cl2 (25 mL), Ph3P
(6.31g, 24.05 mmol) was added in four portions at 3 min
interval at 0 ˚C. Stirring was continued for 1 h at rt and dilu-
ted with petroleum ether (60-80 ˚C). The phosphine oxide
was removed by column chromatography over silica gel
using (1:1) ethyl acetate : pet ether as eluent.
3H), 6.50 (s, 1H), 7.41 (t, 1H, J = 7.3 Hz), 7.52 (t, 2H, J =
7.5 Hz), 7.95 (d, 1H, J = 7.4 Hz), 8.0 (s, 3H), 9.48 (s, 1H);
13C-NMR (CDCl3, 125 MHz) ꢁ: 18, 107.3, 114.6, 115.3,
119.4, 119.7, 125.3, 127.2, 128.4, 129, 129.8, 138.4, 147.5,
152.6, 153.7, 159.3; LCMS: m/z [M + H]+ 304.3. Anal.
Calcd. for C18H13N3O2 : C, 71.28; H, 4.32; N, 13.85 %.
Found: C, 71.39; H, 4.28; N, 13.96 %.
A solution of dibromoalkene (14.20 mmol) in dry THF
(40 mL) at -78 ˚C under nitrogen atmosphere was stirred
with n-BuLi in hexane (29.82 mmol) for 1 h at -78 ˚C. The
reaction mixture was warmed to -25 ˚C and was stirred at
that temperature for further 1 h. The reaction mixture was
quenched with water (20 mL) and extracted with ethylacetate
(3 X 30 mL). Removal of the solvent and flash chromato-
graphy with (1:9) ethyl acetate : pet ether as eluent gave the
desired alkynes (B, C).
7-(4-(4-chlorophenyl)-1H-1,2,3-triazol-1-yl)-4-methyl-2H-
chromen-2-one (3e)
Yellow solid, mp above 230˚C, yield 73%. IR (KBr, cm-
1) ꢀmax: 1706, 1621; H-NMR (CDCl3, 400 MHz) ꢁ: 3.38 (s,
1
3H), 6.50 (s, 1H), 7.60 (d, 2H, J = 8.6 Hz), 7.97 (d, 2H, J =
8.6 Hz), 7.99-8.03 (m, 3H), 9.52 (s, 1H); LCMS: m/z [M +
H]+ 338.2. Anal. Calcd. for C18H12ClN3O2 : C, 64.01; H,
3.58; N, 12.44 %. Found: C, 63.91; H, 3.42; N, 12.31 %.
1-methyl-6-(4-phenyl-1H-1,2,3-triazol-1-yl)quinolin-2(1H)-
one (3f)
General Procedure for [1,2,3] Triazole Synthesis (3a-h)
Yellow solid, mp 212-214˚C, yield 81%. IR (KBr, cm-1)
To a well-stirred solution of the azides 2a-c (4.99 mmol)
and alkynes A-C (5.99 mmol) in DMSO (10 mL), catalytic
amount (10 mol%) of CuI (I) was added and stirred for 1 h at
ꢀ
max: 1735; 1H-NMR (CDCl3, 400 MHz) ꢁ: 3.68 (s, 3H), 6.76

A Short Route to [1,2,3]-Triazolyl Coumarins and Quinolones
Letters in Organic Chemistry, 2009, Vol. 6, No. 1
87
(d, 1H, J = 9.5 Hz), 7.39 (t, 1H, J = 7.4 Hz), 7.51 (t, 2H, J =
7.5 Hz), 7.78 (d, 1H, J = 9.2 Hz), 7.95 (d, 2H, J = 8.3 Hz),
8.04 (d, 1H, J = 9.6 Hz), 8.18 (dd, 1H, J = 9.1, 2.44 Hz),
8.36 (d, 1H, J = 2.4 Hz); 13C-NMR (CDCl3, 125 MHz) ꢀ:
29.2, 116, 119.3, 119.4, 120.4, 122.1, 122.5, 125.2, 128.1,
128.8, 130.1, 130.8, 138.6, 139.3, 147.2, 160.8; LCMS: m/z
[M + H]+ 303.1. Anal. Calcd. for C18H14N4O : C, 71.51; H,
4.67; N, 18.53 %. Found: C, 71.62; H, 4.64; N, 18.64 %.
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6-(4-(4-chlorophenyl)-1H-1,2,3-triazol-1-yl)-1-
methylquinolin-2(1H)-one (3g)
Green solid, mp 260-262˚C, yield 79%. IR (KBr, cm-1)
ꢁ
max: 1643; 1H-NMR (CDCl3, 400 MHz) ꢀ: 3.68 (s, 3H), 6.76
(d, 1H, J = 11.2 Hz), 7.61 (d, 2H, J = 10.0 Hz), 7.79 (d, 1H,
J = 10 Hz), 7.97 (d, 2H, J = 9.6 Hz), 8.04 (d, 1H, J = 10.7
Hz), 8.16 (d, 1H, J = 10.6 Hz), 8.31 (s, 1H), 9.39 (s, 1H);
LCMS: m/z [M + H]+ 337.2. Anal. Calcd. for C18H13ClN4O :
C, 64.19; H, 3.89; N, 16.64 %. Found: C, 64.33; H, 3.88; N,
16.5 %.
[5]
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2003, 1852.
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Silvakumar, K.; Xie, F.; Cash, B.M.; Long, S.; Barnhill, H.N.;
Wang, Q. Org. Lett., 2004, 6, 4603.
1-methyl-6-(4-(4-nitrophenyl)-1H-1,2,3-triazol-1-
yl)quinolin-2(1H)-one (3h)
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Majumdar, K.C.; Muhuri, S.; Rahaman, H.; Islam, R.; Roy, B.
Chem. Lett., 2006, 35, 1430.
Yellow solid, mp 160-162˚C, yield 68%. IR (KBr, cm-1)
max: 1651, 1343; H-NMR (CDCl3, 400 MHz) ꢀ: 3.69 (s,
3H), 7.80 (d, 1H, J = 9.2 Hz), 8.02 – 8.11 (m, 2H), 8.16-8.23
(m, 3H), 8.39 (d, 2H, J = 8.9 Hz), 9.6 (d, 1H, J = 8.9 Hz);
LCMS: m/z [M + H]+ 348.4. Anal. Calcd. for C18H13N5O3 :
C, 62.24; H, 3.77; N, 20.16 %. Found: C, 62.1; H, 3.88; N,
20.35 %.
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6871.
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4231.
1
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[15]
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ACKNOWLEDGEMENTS
We thank the DST (New Delhi) and the CSIR (New
Delhi) for financial assistance. We also thank Mr. Ashesh
Garai, Indian Association for the Cultivation of Science,
Kolkata for helping with the fluorescence data. One of us
(S.M.) is thankful to the DST (New Delhi) for his fellow-
ship.