Synthesis and study of the fluorescent behavior of 3-pyridinecarbonitriles

Article abstract of DOI:10.1007/s00706-009-0116-8

A series of (2E)-3-(1-chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-1-(4- aryl)prop-2-en-1-ones (chalcones) have been synthesized by a new synthetic route. The 3-pyridinecarbonitrile derivatives were synthesized by the Michael reaction of malononitrile (in

Full text of DOI:10.1007/s00706-009-0116-8

Monatsh Chem (2009) 140:655–662
DOI 10.1007/s00706-009-0116-8
ORIGINAL PAPER
Synthesis and study of the fluorescent behavior
of 3-pyridinecarbonitriles
Madhukar N. Jachak Æ Sandeep M. Bagul Æ
Bhausaheb K. Ghotekar Æ Raghunath B. Toche
Received: 9 October 2008 / Accepted: 15 December 2008 / Published online: 5 March 2009
Ó Springer-Verlag 2009
Abstract A series of (2E)-3-(1-chloro-6-methoxy-3,4-
dihydronaphthalen-2-yl)-1-(4-aryl)prop-2-en-1-ones (chal-
cones) have been synthesized by a new synthetic route. The
3-pyridinecarbonitrile derivatives were synthesized by the
Michael reaction of malononitrile (in base) and aroyl-
acetonitriles (in acid) with chalcones in one pot. The
fluorescent properties and quantum yields of these com-
pounds were studied.
Derivatives of pyridines have application in light emit-
ting [3] and electroluminescence devices [4]. Apart from
this, 3-pyridinecarbonitriles have been used as dyes for
synthetic fabrics [5–7] and paper [8, 9]. Pyridine deriva-
tives have been synthesized by using chalcones as a
starting material [10–12]. As a part of our ongoing interest
in this area [13–15] we have reported the synthesis of
pyrazolo[3,4-b]pyridines, pyrazolo[3,4-b]quinolines, pyrazo-
lonaphthyridines, and pyrazolopyridopyrimidines by Fried-
¨
lander condensation of reactive methylene compounds
Keywords Chalcone ꢀ 3-Pyridinecarbonitriles ꢀ
Fluorescence ꢀ Wittig reaction ꢀ Grignard reaction
with 5-aminopyrazole. In our recent communications [16],
the synthesis of highly fluorescent dipyrazolo[3,4-b:3,4-
d]pyridines (DPP) has been reported. These literature reports
and our ongoing research in this area prompted us to synthe-
size 3-pyridinecarbonitriles and to study their fluorescence
behavior.
Introduction
Inspired by the pioneering work of Tang and vanSlyke [1]
on electroluminescence (EL) devices that use organic
molecular materials, research activity on organic light
emitting diodes (OLEDs) has been expanding rapidly and
has progressed substantially in recent years. The LEDs of
this category are of great interest because of their potential
applications for the production of low-cost display prod-
ucts. Continuing efforts include the development of new
efficient materials and ingenious device fabrications [2].
There are many activities focused on blue-light emitting
OLEDs and a wide variety of organic and organometallic
compounds have been utilized for this purpose. Thus a
suitable blue-light emitting material with high brightness
and good thermal stability still remains to be developed.
Results and discussion
The synthesis of acetophenones such as 1-(3,4,5-trime-
thoxyphenyl)ethanone requires lithiation of 3,4,5-
trimethoxybenzoic acid and 3,5-dimethoxybenzoic acid,
which involved multistep and tedious workup [17–19]. To
avoid these multistep syntheses, we have developed a new
route towards the synthesis of chalcones 6. In our strategy
the enone part of chalcone was synthesized at the begin-
ning by starting with ortho-chloroaldehyde 1 [20]. The
Wittig reaction on aldehyde 1 delivered enoic acid 3 in
quantitative yield. The enoic acid 3 was converted to amide
4 by treatment 3 with N-methoxymethanamine hydro-
chloride. The amide 4 was successfully reacted with
substituted aryl magnesium bromide 5 which is obtained
from aryl bromide and magnesium in THF at 0 °C to yield
the desired chalcones 6 in 79–84% yield (Scheme 1). On
M. N. Jachak (&) ꢀ S. M. Bagul ꢀ B. K. Ghotekar ꢀ R. B. Toche
Organic Chemistry Research Center, Department of Chemistry,
K.T.H.M. College, Gangapur Road, Nashik 422 002,
Maharashtra, India
e-mail: mn_jachak@hotmail.com
123

656
M. N. Jachak et al.
Scheme 1
O
Cl
Cl
O
O
P
O
NH
. HCl
CHO
OH
+
Ph
O
O
Ph
Ph
3
R1
1
2
R2
R3
MgBr
Cl
O
R1
Cl
O
R2
R4
O
N
5a-5f
R3
O
O
R4
6a-6f
4
R1
R2
H
R3
H
R4
F
6
a
b
c
d
e
f
H
H
H
H
OMe
H
H
OMe
OMe
H
OMe
H
H
OMe
OMe
OMe
OMe
H
H
OMe OMe
the basis of the coupling constant (J = 15.3 Hz) for ole-
finic protons in compounds 3, 4, and 6 an E-configuration
was assigned to these compounds.
30–35 °C yielded the corresponding 3-pyridinecarbonitr-
iles 7 in good yield (Scheme 2).
In compound 7 the alkoxy group at the C-2 position of
the pyridine ring depends upon the alcohol used in the
reaction. Similar cyclocondensation reactions of chalcones
6 with aroylacetonitriles by heating under reflux in acetic
The chalcones 6 were used as intermediates for the
synthesis of 3-pyridinecarbonitriles. Thus the cyclocon-
densation of chalcones 6 with malononitrile in alcohol at
Scheme 2
OR
NC
O
R1
Cl
Cl
N
R1
R2
R3
R2
R3
CH2(CN)2
ROH
O
O
R4
R4
7a-7m
6a-6c
R
R1 R2 R3 R4
7
a
b
c
R
R1 R2
R3
R4
7
e
Et
H
H
H
OMe
H
Me
Et
H
H
H
F
f
n-Pr
Me
Et
H
OMe
H
H
H
H
H
F
g
h
OMe
OMe
H
OMe
OMe
n-Pr
Me
H
H
H
H
H
F
H
H
d
OMe
H
123

Synthesis and study of fluorescent behavior of 3-pyridinecarbonitriles
657
Scheme 3
X
R1
O
Cl
O
R2
CN
NH4.OAc
NC
N
R1
Cl
+
R2
R3
O
R3
X
AcOH,
Reflux
R4
O
8a-8b
9a-9h
6a-6c
R4
R1
R2
H
R3
R4
X
8
9
a
X
a
H
H
F
F
H
Cl
Cl
H
H
H
H
H
H
Br
Cl
Br
b
b
c
d
e
f
Br
H
OMe
OMe
H
H
H
H
OMe
OMe
OMe Cl
OMe Br
H
acid furnished corresponding 3-pyridinecarbonitriles 9 in
70–75% yield (Scheme 3).
and 9 in the aryl ring at the C-6 position of the pyridine
nucleus has profound influence on the absorption and
emission properties. These findings reveal that 3-pyri-
dinecarbonitriles 7d–7h and 9c–9f substituted with
electron-donating substituents such as a methoxy group
(strong donor) in the aryl ring at C-6 of pyridine enhanced
the UV absorption in the range 378–400 nm, the fluores-
cence maxima in the range of 430–451 nm, and quantum
yields in the range 0.198–0.219. When the substituent is
fluoro (weak donor) in the 3-pyridinecarbonitriles 7a–7c
and 9a and 9b the UV absorption is in the range
376–385 nm and fluorescence maxima are in the range
432–442 nm along with quantum yields in the
range 0.179–0.189. The absorption and fluorescence data
are listed in Table 1. The absorption and emission spectra
of compound 7d are also shown in Fig. 1.
The structures of all these compounds were confirmed
1
by H NMR, IR, and elemental analysis.
Photophysical properties
Compounds 7 and 9 showed absorption and fluorescence in
the near visible region (380–400 nm). It was noted that
incorporation of a substituent in 3-pyridinecarbonitriles 7
Table 1 Photophysical data for the electronic excitation (UV kmax),
fluorescence (Em kmax), and quantum yield (U) of 7a–7h and 9a–9f in
DMSO as the solvent at 25 °C
Cpd. No.
UV kmax/nm
Em kmax/nm
U
7a
7b
7c
7d
7e
7f
385
386
386
397
398
397
399
400
381
376
383
378
386
387
452
444
441
449
439
430
446
441
437
439
441
445
449
451
0.189
0.185
0.179
0.219
0.210
0.198
0.221
0.213
0.189
0.186
0.215
0.210
0.217
0.211
Conclusion
The reactions reported here represent a novel synthetic
route towards chalcones. Highly fluorescent compounds 7
7g
7h
9a
9b
9c
9d
9e
9f
Fig. 1 The absorption (X) and emission (Y) spectra of compound 7d
123

658
M. N. Jachak et al.
the course of 5 min under nitrogen atmosphere. The
reaction mixture was stirred for 1 h, then 1.67 g triethyl-
amine (12 mmol) and 1.17 g N-methoxymethanamine
hydrochloride (12 mmol) were added. After stirring at
room temperature for another 3 h, 50 cm3 water was added
to the resulting reaction mass. The solid obtained was
collected by filtration, washed with 50 cm3 water, and
dried to afford 2.74 g (89%) 4. M.p.: 107–108 °C; 1H
NMR (DMSO-d6): d = 2.6 7 (t, J = 6.9 Hz, 2H, CH2),
2.91 (t, J = 7.0 Hz, 2H, CH2), 3.33 (s, 3H, –N CH3), 3.78
(s, 3H, OCH3), 3.87 (s, 3H, OCH3), 6.65 (d, J = 15.3 Hz,
1H, =CH), 6.74 (d, J = 7.2 Hz, 1H, Ar–H), 6.81 (dd,
J = 2.4, 6.2 Hz, 1H, Ar–H), 7.69 (d, J = 8.1 Hz, 1H,
Ar–H), 8.19 (d, J = 15.3 Hz, 1H, =CH) ppm; 13C NMR
(DMSO-d6); d = 26.41, 31.79, 32.68, 55.57, 62.16,
111.08, 111.21, 121.31, 127.05, 127.17, 132.99, 134.37,
139.01, 147.79, 159.59, 159.89 ppm; IR: vꢀ = 2,937, 1,636,
and 9 were synthesized. Thermal analysis of 7 and 9 by
differential scanning calorimetry (DSC) revealed that they
are thermally stable compounds up to 350 °C. Most
important, fluorescence quantum yields are almost inde-
pendent of solvents and pH and values of around 0.22 are
obtained. The fluorescence properties of these compounds
depend upon the nature of substituents present at the phe-
nyl moiety at the 6-position of the pyridine ring.
Experimental
Melting points: Gallenkamp melting point apparatus; IR
Spectra (KBr-compression mold): Shimadzu IR-408; 1H
NMR (300 MHz), 13C NMR (75 MHz) Spectra: Varian
XL-300 in DMSO-d6 or CDCl3 using TMS as internal
standard; Mass spectra: hp 1100 LC–MSD mass spec-
trometer (positive and negative APCI ion source, 50–
200 V, nitrogen); Elemental analyses (C, H, N, S) were
conducted using the HOSLI CH-Analyzer; the results were
in agreement with calculated values.
1,590, 1,410, 1,337 cm-1
.
General procedure for the synthesis of compounds 6
To a suspension of 15 mmol magnesium foils in 3 cm3 dry
tetrahydrofuran (THF) containing a catalytic amount
(0.02 g) of iodine crystals was added 15 mmol aryl bromide
5 at room temperature. The reaction mixture was stirred for
1 h at room temperature. The Grignard reagent thus formed
was added slowly to a solution of 5 mmol 4 in 5 cm3 dry THF
under nitrogen atmosphere at 0–5 °C and stirred at room
temperature for 1 h. The reaction mixture was cooled at
10 °C and 5 cm3 0.5 M HCl was added at 10–15 °C. The
solvent was evaporated under reduced pressure and the res-
idue was dissolved in 10 cm3 dichloromethane. The organic
layer was washed with 10 cm3 saturated sodium bicarbonate
followed by saturated sodium chloride. The organic layer
was collected and dried over sodium sulfate, and concen-
trated under reduced pressure. The remaining solid was
recrystallized from ethanol.
(2E)-3-(1-Chloro-(6-methoxy-3,4-dihydronaphthalen-
2-yl)acrylic acid (3, C14H13ClO3)
A mixture of 2.225 g 1-chloro-6-methoxy-3,4-dihydro-
naphthalene-2-carbaldehyde (1) [20] (10 mmol) and
4.537 g 2 (13 mmol) was heated under reflux in 10 cm3
dichloromethane for 5 h. The solvent was removed under
reduced pressure and the residue was dissolved in 10 cm3
methanol and 52 cm3 aqueous sodium hydroxide (10%
solution), which was heated under reflux for 4 h. The
solvent was removed under reduced pressure, 15 cm3 water
were added to the residue. The aqueous layer was extracted
with 2 9 15 cm3 dichloromethane to remove triphenyl-
phosphine oxide. The aqueous layer was acidified with 2 M
HCl upon which a solid precipitated which was isolated by
suction filtration to afford 2.30 g (87%) 3. M.p.: 260–
1
261 °C; H NMR (DMSO-d6): d = 2.52 (t, J = 7.0 Hz,
2H, CH2), 2.76 (t, J = 7.2 Hz, 2H, CH2), 3.72 (s, 3H,
OCH3), 6.04 (d, J = 15.3 Hz, 1H, =CH), 6.81 (d,
J = 8.6 Hz, 1H, Ar–H), 6.82 (dd, J = 2.1, 8.2 Hz, 1H,
Ar–H), 7.49 (d, J = 8.1 Hz, 1H, Ar–H), 7.80 (d,
J = 15.3 Hz, 1H, =CH) ppm; 13C NMR (DMSO-d6):
d = 26.89, 31.70, 55.47, 112.04, 112.14, 116.98, 127.08,
127.11, 133.14, 134.47, 138.85, 151.79, 159.43,
170.18 ppm; IR: vꢀ = 3,432, 2,937, 2,832, 1,701, 1,636,
(2E)-3-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
1-(4-fluorophenyl)prop-2-en-1-one (6a, C20H16ClFO2)
Yield 1.49 g (87%); m.p.: 130–131 °C (ethanol); 1H NMR
(CDCl3): d = 2.73 (t, J = 7.1 Hz, 2H, CH2), 2.94 (t,
J = 6.9 Hz, 2H, CH2), 3.87 (s, 3H, OCH3), 6.76 (d,
J = 2.4 Hz, 1H, Ar–H), 6.82 (dd, J = 2.3, 8.7 Hz, 1H, Ar–
H), 7.07 (d, J = 15.3 Hz, 1H, =CH), 7.16 (t, J = 8.2 Hz,
2H, Ar–H), 7.72 (d, J = 8.4 Hz, 1H, Ar–H), 8.01 (t,
J = 6.0 Hz, 2H, Ar–H), 8.28 (d, J = 15.3 Hz, 1H, =CH)
ppm; 13C NMR (CDCl3): d = 29.86, 31.93, 55.44, 111.33,
111.52, 116.12 (2C), 127.14, 127.33, 129.62, 131.25 (2C),
133.38, 133.65, 133.91, 138.76, 148.82, 159.91, 168.90,
189.14 ppm; IR: vꢀ = 2,941, 2,834, 1,647, 1,610, 1,579,
1,590 cm-1
.
(2E)-3-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
N-methoxy-N-methylacrylamide (4, C16H18ClNO3)
To a solution of 2.645 g 3 (10 mmol) in 26 cm3 dry
tetrahydrofuran (THF), 1.944 g 1,10-carbonyldiimidazole
(12 mmol) was added at room temperature, in portions, in
1,498, 1,306 cm-1
.
123

Synthesis and study of fluorescent behavior of 3-pyridinecarbonitriles
659
(2E)-3-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
1-(4-methoxyphenyl)-prop-2-en-1-one (6b, C21H19ClO3)
Yield 1.52 g (86%); m.p.: 127–128 °C (ethanol); 1H NMR
(CDCl3): d = 2.70 (t, J = 7.0 Hz, 2H, CH2), 2.89 (t,
J = 6.2 Hz, 2H, CH2), 3.84 (s, 3H, OCH3), 3.88 (s, 3H,
OCH3), 6.75 (d, J = 2.1 Hz, 1H, Ar–H), 6.78 (dd, J = 2.1,
7.2 Hz, 1H, Ar–H), 6.95 (d, J = 7.2 Hz, 2H, Ar–H), 7.09
(d, J = 15.0 Hz, 1H, = CH), 7.67 (d, J = 7.2 Hz, 1H, Ar–
H), 7.96 (d, J = 6.9 Hz, 2H, Ar–H), 8.23 (d, J = 15.0 Hz,
1H, =CH) ppm; 13C NMR (CDCl3): d = 30.01, 32.64,
55.77, 55.82, 111.17, 111.61, 114.53, 127.51, 127.72 (2C),
128.73, 129.51, 129.96 (2C), 133.84, 134.41, 139.12,
148.93, 159.72, 166.02, 189.51 ppm; IR: vꢀ = 2,939,
(t, J = 7.1 Hz, 2H, CH2), 3.84 (s, 3H, OCH3), 3.85 (s,
3H, OCH3), 3.86 (s, 3H, OCH3), 6.66 (d, J = 2.1 Hz, 1H,
Ar–H), 6.74 (d, J = 1.2 Hz, 1H, Ar–H), 6.80 (dd, J = 2.3,
8.7 Hz, 1H, Ar–H), 7.02 (d, J = 15.6 Hz, 1H, =CH), 7.10
(d, J = 2.1 Hz, 2H, Ar–H), 7.70 (d, J = 8.7 Hz, 1H, Ar–
H), 8.25 (d, J = 15.3 Hz, 1H, =CH) ppm; IR: vꢀ = 2,938,
2,836, 1,652, 1,569, 1,495, 1,315 cm-1
.
(2E)-3-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one
(6f, C23H23ClO5)
Yield 1.64 g (79%); m.p.: 135–136 °C (ethanol); 1H NMR
(300 MHz, CDCl3): d = 2.71 (t, J = 6.9 Hz, 2H, CH2),
2.92 (t, J = 7.0 Hz, 2H, CH2), 3.84 (s, 3H, OCH3), 3.93 (s,
3H, OCH3), 3.94 (s, 3H, OCH3), 3.95 (s, 3H, OCH3), 6.74
(d, J = 2.4 Hz, 1H, Ar–H), 6.80 (dd, J = 2.4, 8.7 Hz, 1H,
Ar–H), 6.99 (d, J = 15.6 Hz, 1H, =CH), 7.22 (d,
J = 2.1 Hz, 2H, Ar–H), 7.70 (d, J = 8.7 Hz, 1H, Ar–H),
8.25 (d, J = 15.3 Hz, 1H, =CH) ppm; IR: vꢀ = 2,938,
2,842, 1,651, 1,596, 1,487, 1,315 cm-1
; MS: m/z
(%) = 356.1 (25) [M ? 2], 354.2 (100) [M], 318.1 (70).
(2E)-3-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
1-(2,4-dimethoxyphenyl)prop-2-en-1-one
(6c, C22H21ClO4)
2,839, 1,653, 1,569, 1,495, 1,344 cm-1
.
Yield 1.59 g (83%); m.p.: 116–117 °C (ethanol); 1H NMR
(CDCl3): d = 2.67 (t, J = 6.4 Hz, 2H, CH2), 2.90 (t,
J = 7.0 Hz, 2H, CH2), 3.86 (s, 3H, OCH3); 3.88 (s, 3H,
OCH3), 3.90 (s, 3H, OCH3), 6.50 (d, J = 1.8 Hz, 1H, Ar–H),
6.58 (dd, J = 2.1, 8.7 Hz, 1H, Ar–H), 6.75 (d, J = 2.1 Hz,
1H, Ar–H), 6.80 (dd, J = 2.1, 8.7 Hz, 1H, Ar–H), 7.11 (d,
J = 15.6 Hz, 1H, =CH), 7.70 (d, J = 8.4 Hz, 1H, Ar–H),
7.75 (d, J = 8.6 Hz, 1H, Ar–H), 8.13 (d, J = 15.6 Hz, 1H,
=CH) ppm; IR: vꢀ = 2,937, 2,834, 1,644, 1,609, 1,585, 1,491,
1,321 cm-1; MS: m/z (%) = 386.1 (28) [M ? 2], 384.1
(100) [M], 348.1 (22), 208.0 (21).
General procedure for the synthesis of 7
A mixture of 6 (0.15 mmol) and malononitrile (0.15 mmol)
in 10 cm3 alcohol containing a catalytic amount (0.005 g)
of potassium hydroxide was stirred at 30–35 °C for 14 h.
The precipitated solid was isolated by filtration, washed
with water, dried, and recrystallized from a suitable solvent
to furnish compounds 7 in 68–74% yield.
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
6-(4-fluorophenyl)-2-methoxynicotinonitrile
(7a, C24H18ClFN2O2)
(2E)-3-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
1-(2,5-dimethoxyphenyl)prop-2-en-1-one
Yield 0.046 g (73%); m.p.: 206–207 °C (methanol);
1H NMR (CDCl3): d = 2.75 (t, J = 7.0 Hz, 2H, CH2),
2.99 (t, J = 6.9 Hz, 2H, CH2), 3.84 (s, 3H, OCH3), 4.17 (s,
3H, OCH3), 6.76 (d, J = 2.3 Hz, 1H, Ar–H), 6.79 (dd,
J = 2.1, 7.8 Hz, 1H, Ar–H), 7.16 (t, J = 8.1 Hz, 2H, Ar–
H), 7.32 (s, 1H, Ar–H), 7.63 (d, J = 8.4 Hz, 1H, Ar–H),
8.06 (t, J = 7.2 Hz, 2H, Ar–H) ppm; 13C NMR (CDCl3):
d = 20.02, 32.24, 55.23, 55.54, 94.29, 111.19, 111.42,
116.01 (2C), 116.29, 120.21, 123.09, 127.01, 129.13 (2C),
129.49, 132.21, 133.19, 139.14, 139.62, 141.12, 159.65,
160.70, 164.47 ppm; IR: vꢀ = 2,956, 2,935, 2,230, 1,600,
(6d, C22H21ClO4)
Yield 1.60 g (83%); m.p.: 119–120 °C (ethanol); 1H NMR
(CDCl3): d = 2.67 (t, J = 7.0 Hz, 2H, CH2), 2.90 (t,
J = 7.4 Hz, 2H, CH2), 3.85 (s, 3H, OCH3), 3.86 (s, 3H,
OCH3), 3.89 (s, 3H, OCH3), 6.50 (d, J = 1.8 Hz, 1H, Ar–H),
6.58 (dd, J = 2.1, 8.7 Hz, 1H, Ar–H), 6.75 (d, J = 2.1 Hz,
1H, Ar–H); 6.80 (dd, J = 2.1, 8.7 Hz, 1H, Ar–H); 7.11 (d,
J = 15.6 Hz, 1H, =CH); 7.70 (d, J = 8.4 Hz, 1H, Ar–H),
7.75 (d, J = 8.6 Hz, 1H, Ar–H), 8.13 (d, J = 15.6 Hz, 1H,
=CH) ppm; 13C NMR (CDCl3): d = 30.31, 32.06, 55.40,
55.42, 55.44, 110.91, 111.21, 115.32, 116.11, 120.99,
121.81, 127.33, 127.62, 128.81, 133.57, 134.51, 139.03,
149.21, 153.75, 153.81, 159.97, 189.52 ppm; IR: vꢀ = 2,937,
2,835, 1,646, 1,610, 1,589, 1,495, 1,328 cm-1; MS: m/z
(%) = 416.1 (31) [M ? 2], 414.1 (100) [M], 379.2 (23).
1,580, 1,543, 1,449, 1,350, 1,263 cm-1
.
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-2-eth-
oxy-6-(4-fluorophenyl)nicotinonitrile
(7b, C25H20ClFN2O2)
(2E)-3-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
1-(3,5-dimethoxyphenyl)prop-2-en-1-one
(6e, C22H21ClO4)
Yield 1.57 g (82%); m.p.: 114–115 °C (ethanol); 1H NMR
(CDCl3): d = 2.69 (t, J = 7.2 Hz, 2H, CH2), 2.91
Yield 0.047 g (72%); m.p.: 163–164 °C (ethanol); 1H
NMR (CDCl3): d = 1.54 (t, J = 7.2 Hz, 3H, CH3), 2.75 (t,
J = 7.1 Hz, 2H, CH2), 3.02 (t, J = 6.9 Hz, 2H, CH2), 3.84
(s, 3H, OCH3), 4.63 (q, J = 6.8 Hz, 2H, CH2), 6.74 (d,
J = 2.1 Hz, 1H, Ar–H), 6.79 (dd, J = 2.3, 8.1 Hz, 1H,
123

660
M. N. Jachak et al.
Ar–H), 7.15 (t, J = 8.1 Hz, 2H, Ar–H), 7.29 (s, 1H, Ar–H),
7.62 (d, J = 8.1 Hz, 1H, Ar–H), 8.04 (t, J = 7.4 Hz, 2H,
Ar–H) ppm; IR: vꢀ = 2,935, 2,218, 1,607, 1,585, 1,431,
1,324, 1,257 cm-1; MS: m/z (%) = 436.5 (38) [M ? 2],
434.6 (100) [M], 390.6 (21), 278.2 (43).
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
6-(4-methoxyphenyl)-2-propoxynicotinonitrile
(7f, C27H25ClN2O3)
Yield 0.048 g (69%); m.p.: 131–132 °C (methanol); 1H
NMR (CDCl3): d = 1.12 (t, J = 7.0 Hz, 3H, CH3), 1.92
(sext, J = 6.9 Hz, 2H, CH2), 2.76 (t, J = 6.9 Hz, 2H,
CH2), 3.04 (t, J = 7.2 Hz, 2H, CH2), 3.87 (s, 3H, OCH3),
3.90 (s, 3H, OCH3), 4.55 (t, J = 6.8 Hz, 2H, CH2), 6.77 (d,
J = 2.4 Hz, 1H, Ar–H), 6.83 (dd, J = 2.7, 8.7 Hz, 1H, Ar–
H), 7.02 (d, J = 9.0 Hz, 2H, Ar–H), 7.31 (s, 1H, Ar–H),
7.66 (d, J = 8.4 Hz, 1H, Ar–H), 8.05 (t, J = 8.7 Hz, 2H,
Ar–H) ppm; 13C NMR (CDCl3): d = 10.59, 20.09, 22.24,
28.45, 55.39, 55.44, 68.82, 102.71, 111.45, 112.13, 114.22
(2C), 115.28, 120.90, 123.14, 126.88, 128.83, 128.97 (2C),
130.03, 132.31, 138.87, 139.35, 141.56, 159.26, 159.92,
164.39 ppm; IR: vꢀ = 2,956, 2,871, 2,220, 1,600, 1,540,
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-6-
(4-fluorophenyl)-2-propoxynicotinonitrile
(7c, C26H22ClFN2O2)
Yield 0.048 g (71%); m.p.: 139–140 °C (methanol); 1H
NMR (CDCl3): d = 1.6 (t, J = 6.8 Hz, 3H, CH3), 1.92
(sext, J = 6.4 Hz, 2H, CH2), 2.75 (t, J = 7.4 Hz, 2H,
CH2), 3.12 (t, J = 7.0 Hz, 2H, CH2), 3.84 (s, 3H, OCH3),
4.53 (t, J = 6.9 Hz, 2H, CH2), 6.73 (d, J = 2.3 Hz, 1H,
Ar–H), 6.81 (dd, J = 2.1, 7.4 Hz, 1H, Ar–H), 7.15 (t,
J = 8.1 Hz, 2H, Ar-H), 7.28 (s, 1H, Ar–H), 7.29 (d,
J = 8.1 Hz, 1H, Ar–H), 8.05 (t, J = 8.4 Hz, 2H, Ar–H)
ppm; 13C NMR (CDCl3): d = 10.22, 20.29, 22.12, 32.80,
55.62, 69.92, 94.69, 111.41, 111.60, 116.03 (2C), 116.70,
120.62, 123.59, 127.19, 129.23 (2C), 130.31, 131.92,
132.83, 139.24, 139.69, 141.72, 159.85, 161.20,
163.49 ppm; IR: vꢀ = 2,951, 2,939, 2,231, 1,601, 1,576,
1,422, 1,345 cm-1
.
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
6-(2,5-dimethoxyphenyl)-2-methoxynicotinonitrile
(7g, C26H23ClN2O4)
Yield 0.050 g (72%); m.p.: 173–174 °C (methanol); 1H
NMR (CDCl3): d = 2.78 (t, J = 7.1 Hz, 2H, CH2), 3.03 (t,
J = 6.4 Hz, 2H, CH2), 3.83 (s, 3H, OCH3), 3.84 (s, 3H,
OCH3), 3.85 (s, 3H, OCH3), 3.87 (s, 3H, OCH3), 6.78 (d,
J = 2.3 Hz, 1H, Ar–H), 6.83 (dd, J = 2.4, 8.4 Hz, 1H, Ar–
H), 6.98 (dd, J = 2.1, 8.2 Hz, 2H, Ar–H), 7.62 (d,
J = 2.4 Hz, 1H, Ar–H), 7.66 (s, 1H, Ar–H), 7.67 (d,
J = 8.7 Hz, 1H, Ar–H) ppm; IR: vꢀ = 2,956, 2,931, 2,231,
1,469, 1,359, 1,241 cm-1
.
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
6-(4-methoxyphenyl)-2-methoxynicotinonitrile
(7d, C25H21ClN2O3)
Yield 0.047 g (72%); m.p.: 182–183 °C (methanol); 1H
NMR (CDCl3): d = 2.75 (t, J = 6.9 Hz, 2H, CH2), 3.00 (t,
J = 7.8 Hz, 2H, CH2), 3.84 (s, 3H, OCH3), 3.86 (s, 3H,
OCH3), 3.84 (s, 3H, OCH3), 6.76 (d, J = 2.3 Hz, 1H, Ar–
H), 6.79 (dd, J = 2.1, 9.3 Hz, 1H, Ar–H), 7.16 (d,
J = 8.1 Hz, 2H, Ar–H), 7.32 (s, 1H, Ar–H), 7.63 (d,
J = 8.4 Hz, 1H, Ar–H), 8.06 (d, J = 8.2 Hz, 2H, Ar–H)
ppm; IR: vꢀ = 2,917, 2,848, 2,219, 1,608, 1,583, 1,423,
1,600, 1,580, 1,538, 1,443, 1,350 cm-1
.
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-
2-ethoxy-6-(2,5-dimethoxyphenyl)nicotinonitrile
(7h, C27H25ClN2O4)
Yield 0.050 g (70%); m.p.: 150–151 °C (ethanol); 1H
NMR (300 MHz, CDCl3): d = 1.52 (t, J = 6.9 Hz, 3H,
CH3); 2.78 (t, J = 7.2 Hz, 2H, CH2); 3.04 (t, J = 6.8 Hz,
2H, CH2); 3.84 (s, 3H, OCH3); 3.85 (s, 3H, OCH3); 3.86 (s,
3H, OCH3); 4.63 (t, J = 7.8 Hz, 2H, CH2); 6.77 (d,
J = 2.3 Hz, 1H, Ar–H), 6.83 (dd, J = 2.4, 8.4 Hz, 1H,
Ar–H); 6.98 (dd, J = 2.1, 8.2 Hz, 2H, Ar–H), 7.62 (d,
J = 2.4 Hz, 1H, Ar–H), 7.66 (s, 1H, Ar–H), 7.67 (d,
J = 8.7 Hz, 1H, Ar–H) ppm; IR: vꢀ = 2,974, 2,928, 2,218,
1,338 cm-1
.
4-(1-Chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-2-
ethoxy-6-(4-ethoxyphenyl) nicotinonitrile
(7e, C26H23ClN2O3)
Yield 0.048 g (72%); m.p.: 137–138 °C (ethanol); 1H
NMR (CDCl3): d = 1.50 (t, J = 7.0 Hz, 3H, CH3), 2.74 (t,
J = 7.4 Hz, 2H, CH2), 3.01 (t, J = 7.0 Hz, 2H, CH2), 3.84
(s, 3H, OCH3),; 3.87 (s, 3H, OCH3), 4.64 (t, J = 6.9 Hz,
2H, CH2), 6.73 (d, J = 2.1 Hz, 1H, Ar–H), 6.80 (dd,
J = 2.3, 8.1 Hz, 1H, Ar–H), 6.98 (d, J = 8.4 Hz, 2H, Ar–
H), 7.26 (s, 1H, Ar–H), 7.63 (d, J = 8.1 Hz, 1H, Ar–H),
8.02 (d, J = 8.1 Hz, 2H, Ar–H) ppm; 13C NMR (CDCl3):
d = 14.09, 19.71, 33.17, 55.66, 55.91, 64.74, 94.52,
111.21, 111.37, 114.31 (2C), 116.90, 120.52, 122.88,
127.41, 128.42, 128.87 (2C), 130.62, 132.50, 139.01,
139.51, 141.91, 159.03, 159.92, 163.77 ppm; IR:
vꢀ = 2,928, 2,848, 2,220, 1,605, 1,583, 1,515, 1,474,
1,603, 1,574, 1,543, 1,449, 1,347, 1,268 cm-1
.
General procedure for the synthesis of 9
A mixture of 6 (0.15 mmol), aroylacetonitriles 8a or 8b
(0.15 mmol), and 0.035 g ammonium acetate (0.45 mmol)
in 10 cm3 acetic acid was heated under reflux for 12 h. The
reaction mixture was cooled to room temperature, the solid
precipitated was isolated by filtration, washed with 5 cm3
water, and dried.
1,257 cm-1
.
123

Synthesis and study of fluorescent behavior of 3-pyridinecarbonitriles
661
2-(4-Chlorophenyl)-4-(1-chloro-6-methoxy-3,4-di-
hydronaphthalen-2-yl)-6-(4-fluorophenyl)nicotinonitrile
(9a, C29H19Cl2FN2O)
2-(4-Bromophenyl)-4-(1-chloro-6-methoxy-3,4-di-
hydronaphthalen-2-yl)-6-(4-methoxyphenyl)nicotinonitrile
(9d, C30H22BrClN2O2)
Yield 0.055 g (73%); m.p.: 188–189 °C; 1H NMR
(CDCl3): d = 2.79 (t, J = 7.1 Hz, 2H, CH2), 3.01 (t,
J = 7.8 Hz, 2H, CH2), 3.80 (s, 3H, OCH3), 6.90 (d,
J = 2.3 Hz, 1H, Ar–H), 6.94 (dd, J = 2.4, 8.3 Hz, 1H, Ar–
H), 7.39 (t, J = 8.7 Hz, 2H, Ar–H), 7.57 (s 1H, Ar–H),
7.67 (d, J = 8.4 Hz, 2H, Ar–H), 8.01 (d, J = 8.1 Hz, 2H,
Ar–H), 8.25 (d, J = 8.4 Hz, 1H, Ar–H), 8.35 (t,
J = 6.6 Hz, 2H, Ar–H) ppm; 13C NMR (CDCl3):
d = 27.99, 30.06, 54.83, 105.04, 112.36, 114.03, 116.41,
116.58, 117.31, 118.83, 124.58, 126.65, 129.16 (2C),
130.27, 130.43, 130.64, 131.11, 131.37 (2C), 133.63,
135.71, 136.67, 138.59, 155.82, 158.11, 159.99, 160.59,
163.67 ppm; IR: vꢀ = 2,959, 2,837, 2,363, 2,344, 1,670,
1,599, 1,410, 1,390, 1,284 cm-1; MS: m/z (%) = 505.2
(32) [M ? 4], 503.2 (26) [M ? 2], 501.3 (100) [M], 430.1
(58), 326.3 (24).
Yield 0.06 g (72%); m.p.: 188–189 °C; 1H NMR
(CDCl3): d = 2.81 (t, J = 7.6 Hz, 2H, CH2), 3.05 (t,
J = 6.8 Hz, 2H, CH2), 3.83 (s, 3H, OCH3), 3.85 (s, 3H,
OCH3), 6.77 (d, J = 2.4 Hz, 1H, Ar–H), 6.82 (dd,
J = 2.7, 6.9 Hz, 1H, Ar–H), 7.00 (d, J = 8.4 Hz, 2H,
Ar–H), 7.58 (d, J = 8.7 Hz, 2H, Ar–H), 7.68 (s, 1H, Ar–
H), 7.74 (d, J = 8.7 Hz, 2H, Ar–H), 7.95 (d,
J = 8.4 Hz, 1H, Ar–H), 8.06 (d, J = 9.0 Hz, 2H, Ar–
H) ppm; IR: vꢀ = 2,940, 2,828, 2,336, 2,234, 1,571,
1,487, 1,270 cm-1
.
2-(4-Chlorophenyl)-4-(1-chloro-6-methoxy-3,4-di-
hydronaphthalen-2-yl)-6-(2,5-dimethoxyphenyl)nicotino-
nitrile (9e, C31H24Cl2N2O3)
Yield 0.057 g (70%); m.p.: 182–183 °C; 1H NMR
(300 MHz, CDCl3): d = 2.78 (t, J = 7.2 Hz, 2H, CH2),
3.02 (t, J = 7.8 Hz, 2H, CH2), 3.86 (s, 3H, OCH3), 3.87 (s,
3H, OCH3), 3.88 (s, 3H, OCH3), 6.79 (d, J = 2.4 Hz, 1H,
Ar–H), 6.82 (d, J = 2.3, 8.2 Hz, 1H, Ar–H), 6.80 (dd,
J = 2.1, 6.7 Hz, 1H, Ar–H), 6.89 (d, J = 2.3 Hz, 1H, Ar–
H), 7.01 (dd, J = 8.7 Hz, 1H, Ar–H), 7.53 (d, J = 8.7 Hz,
2H, Ar–H), 7.61 (d, J = 2.4 Hz, 1H, Ar–H), 7.67 (d,
J = 8.7 Hz, 1H, Ar–H), 7.81 (s, 1H, Ar–H), 8.21 (d,
J = 8.7 Hz, 2H, Ar–H) ppm; IR (KBr): vꢀ = 2,923, 2,869,
2-(4-Bromophenyl)-4-(1-chloro-6-methoxy-3,4-di-
hydronaphthalen-2-yl)-6-(4-flurophenyl)nicotinonitrile
(9b, C29H19BrC1FN2O)
Yield 0.059 g (72%); m.p.: 201–202 °C; 1H NMR
(CDCl3): d = 2.82 (t, J = 6.9 Hz, 2H, CH2), 3.03 (t,
J = 7.2 Hz, 2H, CH2), 3.87 (s, 3H, OCH3), 6.90 (d,
J = 2.1 Hz, 1H, Ar–H), 6.95 (dd, J = 2.3, 8.7 Hz, 1H, Ar–
H), 7.40 (t, J = 8.6 Hz, 2H, Ar–H), 7.82 (d, J = 8.2 Hz,
2H, Ar–H), 7.95 (d, J = 8.7 Hz, 2H, Ar–H), 8.25 (d,
J = 8.3 Hz, 1H, Ar–H), 8.27 (s 1H, Ar–H), 8.36 (t,
J = 8.7 Hz, 2H, Ar–H) ppm; 13C NMR (CDCl3):
d = 27.89, 31.14, 55.61, 104.84, 112.55, 113.93, 116.43
(2C), 117.63, 118.91, 121.79, 126.82, 129.28 (2C), 129.97
(2C), 130.88, 132.21, 132.39 (2C), 132.59, 134.78, 136.34,
138.85, 154.98, 158.35, 160.04, 161.01, 163.89 ppm; IR:
vꢀ = 2,979, 2,828, 2,347, 2,326, 1,661, 1,615, 1,423, 1,401,
2,309, 2,266, 1,578, 1,458, 1,271 cm-1
.
2-(4-Bromophenyl)-4-(1-chloro-6-methoxy-3,4-di-
hydronaphthalen-2-yl)-6-(2,5-dimethoxyphenyl)nicotino-
nitrile (9f, C31H24BrClN2O3)
Yield 0.062 g (70%); m.p.: 198–199 °C; 1H NMR
(CDCl3): d = 2.80 (t, J = 7.0 Hz, 2H, CH2), 3.04 (t,
J = 7.2 Hz, 2H, CH2), 3.85 (s, 3H, OCH3), 3.86 (s, 3H,
OCH3), 3.87 (s, 3H, OCH3), 6.79 (d, J = 2.1 Hz, 1H,
Ar–H), 6.84 (dd, J = 2.4, 8.7 Hz, 1H, Ar–H), 6.99 (d,
J = 2.4 Hz, 1H, Ar–H), 7.01 (dd, J = 8.7 Hz, 1H, Ar–
H), 7.58 (d, J = 8.7 Hz, 2H, Ar–H), 7.64 (d,
J = 2.4 Hz, 1H, Ar–H), 7.70 (d, J = 8.7 Hz, 1H, Ar–
H), 7.99 (d, J = 8.7 Hz, 2H, Ar–H), 8.02 (s, 1H, Ar–H)
ppm; IR: vꢀ = 3,012, 2,815, 2,342, 2,236, 1,558, 1,507,
1,274 cm-1
.
2-(4-Chlorophenyl)-4-(1-chloro-6-methoxy-3,4-di-
hydronaphthalen-2-yl)-6-(4-methoxyphenyl)nicotinonitrile
(9c, C30H22Cl2N2O2)
Yield 0.055 g (71%); m.p.: 176–177 °C; 1H NMR
(CDCl3): d = 2.79 (t, J = 6.6 Hz, 2H, CH2), 3.02 (t,
J = 6.8 Hz, 2H, CH2), 3.83 (s, 3H, OCH3), 3.86 (s, 3H,
OCH3), 6.75 (d, J = 2.4 Hz, 1H, Ar–H), 6.79 (dd, J = 2.7,
6.9 Hz, 1H, Ar–H), 7.00 (d, J = 9.0 Hz, 2H, Ar–H), 7.49
(d, J = 8.7 Hz, 2H, Ar–H), 7.65 (s, 1H, Ar–H), 7.78 (d,
J = 8.7 Hz, 2H, Ar–H), 7.98 (d, J = 8.4 Hz, 1H, Ar–H),
8.10 (d, J = 9.0 Hz, 2H, Ar–H) ppm; IR: vꢀ = 2,933, 2,839,
1,318 cm-1
.
Acknowledgments The authors thank UGC, New Delhi, India for
the financial assistance to this research project. We thank Professor
D.D. Dhavale, Department of Chemistry, University of Pune, India
for his valuable co-operation in the measurement of fluorescence
properties. The authors also thank authorities of NDMVP Samaj’s and
KTHM College, Nashik for facilities.
2,331, 2,336, 1,578, 1,497, 1,278 cm-1
.
123

662
M. N. Jachak et al.
10. Rotkiewicz K, Rettig W, Kohler G, Rechthaler K, Danel A,
Grabka D (2004) Chem Phys 307:45
References
11. Kapturkiewicz A, Herbich J, Nowacki J (1997) Chem Phys Lett
275:355
12. Herbich J, Kapturkiewicz A (1997) Chem Phys Lett 273:8
13. Jachak M, Avale A, Tantak C, Toche R, Reidlinger C, Stadlbauer
W (2005) J Heterocyl Chem 42:1311
14. Jachak M, Avale A, Medhane V, Toche R (2006) J Heterocyl
Chem 43:1169
15. Jachak M, Avale A, Toche R, Sabnis R (2007) J Heterocyl Chem
44:343
16. Jachak M, Kendre D, Toche R (2007) Tetrahedron 63:11000
17. Anderson A, Greef HF (1952) J Am Chem Soc 5:2923
18. Rubottom G, Kim C-w (1983) J Org Chem 48:1550
19. Peterson J, Adam Hill W (1996) J Med Chem 39:3790
20. Konwar D, Boruach R (1997) Ind J Chem 36B:918
1. Tang C, VanSlyke S (1987) Appl Phys Lett 51:913
2. Miyata S, Nalwa H (1997) Organic electroluminescent materials
and devices, Breach, Amsterdam
3. Piorun D, Parusel A, Rechthaler K, Rotkiewicz K, Kohler C
(1999) J Photochem Potobiol A Chem 129:33
4. Butler T, Patel N, Robert M, Baynes N (2006) PCT, Int Appl
WO, 2005019159, Chem Abstr 144:378759
5. Rangnekar D, Kanetkar V (1990) Indian J Fibre Text Res 15:132
6. Etzbach K, Lamm G, Loeffler H, Reichelt H, Sens R (1990) Ger
Patent DE 3,820,313(Cl. B41M5/26), Chem. Abstr 112:218962
7. Dehnert J, Lamm G, Loeffler H, Reichelt H, Sens R (1988) Ger
Patent DE 3,615,093(Cl. C09 B43/128), Chem. Abstr 108:57889
8. Basta A, Girgis A, El-Saied H (2002) Dyes Pigments 54:1
9. Dehnert J (1989) Ger Patent DE 3,707,715 (Cl C09 B49/02),
Chem Abstr 110:156102
123