Michael addition of dimedone with α,β-unsaturated ketones: Synthesis of quinoline and chromene derivatives

Article abstract of DOI:10.1002/jhet.5570450305

(Chemical Equation Presented) A series of quinoline and chromene derivatives has been synthesized by Michael addition of dimedone 1 with 2-aroyl-3-arylacrylonitrile 2 and study of absorption and fluorescence maxima of quinolines.

Full text of DOI:10.1002/jhet.5570450305

May-Jun 2008
667
Michael Addition of Dimedone with α,β-unsaturated Ketones:
Synthesis of Quinoline and Chromene Derivatives
Dhananjay B. Kendre, Raghunath B. Toche and Madhukar N. Jachak*
Organic Chemistry Research Center, Department of Chemistry, K. R. T. Arts, B. H. Commerce and A. M.
Science College,
Gangapur road, Nashik-422002, (M. S.), India
dken10@gmail.com
Received February 2, 2007
Ar1
CN
O
Ar1
CN
X
O
Ar1
CN
X
O
+
+
H
Ar
O
O
Ar
O
Ar
X = NH, O
A series of quinoline and chromene derivatives has been synthesized by Michael addition of dimedone 1
with 2-aroyl-3-arylacrylonitrile 2 and study of absorption and fluorescence maxima of quinolines.
J. Heterocyclic Chem., 45, 667 (2008).
reaction. As part of our continued interest [16,17] in the
synthesis of novel heterocyclic compo- unds, recently we
have reported the synthesis of pyrazolo[3,4-b]pyridine,
pyrazolopyridopyrimidine and pyrazolo- quinoline by the
Friedländer condensation of 5-amino- pyrazole-4-carbal-
dehyde with various reactive methylene compounds and
the synthesis of benzo[h]quinolines, benzo[h]chromenes
[18] by Michael addition of 6-meth-oxy-1-tetralone with
2-aroyl-3-arylacrylonitrile and ben-zylidenemalononitrile.
In this communication we wish to report a very simple
route for the synthesis of quinoline and chromene
derivatives by Michael addition of dime- done 1 with 2-
aroyl-3-arylacry-lonitrile 2 and the study of photophysical
properties of quinoline derivatives.
INTRODUCTION
The Michael addition is an extremely useful and
versatile method for the direct construction of pyridine and
pyran ring in organic synthesis. In recent years an
increasing interest has been focused on the synthesis of
fluorescent compounds owing to their significant biolo-
gical applications in the medicinal chemistry [1,2]. In
particular these compounds have important application in
the field of dyes [3] and are used in the security pap-
ers[4]. Nowadays the fluorescent compounds are
extensively used as a small molecule organic antennas in
the study of luminescence resonance transfer (LRET)
techniques [5]. The remarkable applications of these
compounds not only attracted many chemists to synthesize
such type of compounds but also became an active
research area of continuing interest [6]. Several naturally
occurring and synthetic compounds containing the
quinoline [7] derivatives possess interesting pharma-
ceutical properties for example non-nucleoside reverse
transcriptase inhibitor of human immunodeficiency virus-1
(HIV-1) [8,9]. Quinolines are also reported to posses
antitumor, antibacterial [10] and cardiovascular activities
[11,12].
RESULTS AND DISCUSSION
Thus the Michael addition of dimedone 1 with 2-aroyl-3-
arylacrylonitrile 2 by refluxing with ammonium- acetete in
absolute ethanol, containing catalytic amount of acetic acid
for 6 hours afforded a mixture of compo- unds 3 and 4 in
good yield. This mixture of compound 3 and 4 were
separated by column chromatography using acetone/
toluene as the eluent in 1:9 ratio afforded the compounds 3
and 4 in the ratio 30:55 % yield respectively. The structures
On the other hand chromenes are an important class of
compounds which have received considerable attention in
recent years due to their wide range of biological
activities [13]. Compounds with these ring systems have
diverse pharmacological activities such as anticoagulant,
anti-cancer, spasmolytic, diuretic, anti-anacaphylactia
[14]. The 4H-chromens also constitute the structural unit
of series of natural products [15]. These literature reports
encourage us to develop a new route towards the synthesis
of quinoline and chromene derivatives in a single step
1
of 3a and 4a were confirmed by ir, H nmr, 13C nmr and
elemental analysis for example the ir spectrum of 3a
showed bands at 3280, 2198 and 1622 for N-H, CN and
1
carbonyl stretching respectively. The H nmr spectrum of
compound 3a showed a singlet at δ 1.01 and 1.12 for 6
protons of two methyl groups, multiplet at δ 2.14 due to the
4 protons of two methylene groups, a singlet at δ 4.74
corresponding to C4H and the broad singlet at δ 6.21 for N-
H proton. The 13C nmr spectrum of this compound exhibits

668
D. Kendre, R. Toche, M. Jachak
Vol 45
Scheme 1
H
N
H
1
Ar
1
N
Ar
EtOH
+
CH3COONH4
CN
CN
Ar
O
O
O
Ar
O
1
Ar
O
3a-f
+
H
4a-f
CN
O
Ar
1
O
Ar
1
O
Ar
2a-f
1
Xylene
+
Triethylamine
CN
CN
Ar
O
O
O
Ar
5a-f
2,3,4,5,6 Ar
Ar1
p-Cl-C6H4
p-Cl-C6H4
p-Cl-C6H4
a p-Cl-C6H4
b m-Cl-C6H4
c p-F-C6H4
6a-f
d
p-Cl-C H p-Br-C6H4
6
4
p-Br-C6H4
e m-Cl-C6H4
f p-F-C6H4 p-Br-C6H4
peaks at δ 22, 32, 40, 44, 50, 116 for gem dimethyl and C4,
C6, C7, C8 and cyanide carbons respectively and carbonyl
carbon appears at δ 190. The elemental analysis obtained is
in agreement with the molecular formula. Similarly the
structure of compound 4a was confirmed by ir, 1H nmr, 13C
nmr and elemental analysis for example the ir spectrum of
compound 4a showed bands at 3178, 2214, 1641 for N-H,
elemental analysis obtained is in agreement with the
molecular formula. Analogously the structure of compound
1
6a was confirmed by ir, H nmr, 13C nmr and elemental
analysis for instance the ir spectrum of compound 6a showed
bands at 2210, 1641 for CN and carbonyl group. The 1H nmr
spectrum of 6a showed a singlet at δ 1.03 and 1.06 for 12
protons of four methyl groups, multiplet at δ 2.11 for the 8
protons of four methylene groups and a singlet at δ 5.07
corresponding to the C4H. Further this structure was
confirmed by 13C nmr which is given in the experimental part
and the elemental analysis is in agreement with the molecular
formula. Similarly, the structures of bromo derivatives 5d and
6d were confirmed.
After synthesis of all these compounds, it was noted that
the quinoline derivatives showed good fluorescence
properties. So we further studied the photo- physical
properties of quinoline derivatives 3 and 4. It was noted
that compounds 3 showed UV absorption in the range 357-
369 nm and fluorescence maxima in the range 405-420 nm.
While the compounds 4 showed slightly better absorption
and emission values. The absorption and emission data of
quinolines 3 and 4 are given in the Table 1.
1
CN and carbonyl group. The H nmr spectrum of 4a
showed a singlet at δ 1.01 and 1.09 for 12 protons of four
methyl groups, multiplet at δ 2.17 for the 8 protons of four
methylene groups, a singlet at δ 5.07 corresponding to the
C4H and a broad singlet at δ 6.78 due to the N-H proton.
Further this structure was confirmed by 13C nmr which is in
agreement with the structure proposed. Similarly, the
structures of bromo- derivatives 3d and 4d were confirmed.
Analogously the Michael addition of dimedone 1 with 2-
aroyl-3-arylacrylonitrile 2 by refluxing in xylene cont-aining
catalytic amount of triethylamine also afforded a mixture of
compounds 5 and 6 in good yield. This mixture of compounds
5 and 6 were separated by column chromatography using
acetone/toluene as the eluent in 1:10 ratio afforded the titled
compounds 5 and 6 in the ratio 25:55 % yield respectively.
The structures of 5a and 6a were confirmed by ir, 1H nmr, 13C
nmr and elemental analysis for example the ir spectrum of 5a
showed bands at 2215, 1622 for CN and carbonyl group. The
1H nmr spectrum of compound 5a showed a singlet at δ 1.03
and 1.17 for 6 protons of two methyl groups, multiplet at δ
2.16 due to the 4 protons of two methylene groups and a
singlet at δ 4.73 corresponding to C4H. The 13C nmr spectrum
of this compound exhibit a peaks at δ 25, 31, 40, 44, 52, 116
for gemdimethyl and C4, C6, C7, C8 and cyanide carbon
respectively and carbonyl carbon appears at δ 198. The
Figure 1. Tubes showing the fluorescence of 3a and 4a in methanol
under the UV light.

May-Jun 2008
Michael Addition of Dimedone with α,β-unsaturated Ketones
669
arylacrylonitrile (2) (10 mmol) and ammonium acetate (20
mmol) in absolute ethanol (20 mL) containing catalytic amount
of acetic acid (5 mL) was heated under reflux for 6 hours. The
completion of reaction was monitored by thin layer
chromatography (TLC). Then the solution was allowed to cool
and poured in cold water (100 mL). A colorless solid
precipitated out was filtered, washed with water and dried. It
contained two compounds, the mixture obtained were separated
by column chromatography using acetone/toluene as eluent in
1:10 ratio afforded the compounds (3) and (4) in 30:55 % yield
respectively.
The sample tubes showing the fluorescence of 3a and
4a in methanol under the UV light are shown in Figure 1.
Table 1
The Absorbance, Emission λmax and Quantum yield
of quinolines (3a-f and 4a-f ).
Compd.
Absorbance
Emission
Quantum
λmax (nm)
λmax (nm)
Yield (ΦF)
(3a)
(3b)
(3c)
(3d)
(3e)
(3f)
(4a)
(4b)
(4c)
(4d)
(4e)
(4f)
369
359
362
353
360
364
369
372
383
375
384
383
405
412
420
408
417
418
426
420
419
422
435
440
0.112
0.123
0.145
0.122
0.126
0.129
0.149
0.132
0.131
0.139
0.149
0.151
2,4-Bis(4-chlorophenyl)-1,4,5,6,7,8-hexahydro-7,7-dimeth-
yl-5-oxoquinoline-3-carbonitrile (3a). This compound was
obtained as colorless prism (methanol), 0.84 g (20 %), mp 185-
186 °C; ir: (potassium bromide): 3280, 3084, 2823, 2198, 1622,
1
1153, 842 cm-1; H nmr: (CDCl3) δ 1.01 (s, 3H, CH3), 1.12 (s,
3H, CH3), 2.14 (m, 4H, 2CH2), 4.74 (s, 1H, C4H), 6.21 (bs, 1H,
N-H), 7.01 (m, 8H, Ar); 13C nmr: (CDCl3) δ 22, 28, 32, 40, 44,
50, 92, 116, 118, 119, 123, 124, 126, 129, 131, 135, 138, 156,
160, 190. Anal. Calcd. for C24 H20 Cl2 N2 O: C, 68.09; H, 4.76;
N, 6.62. Found: C, 68.19; H, 4.84; N, 6.70.
4-(3-Chlorophenyl)-2-(4-chlorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-oxoquinoline-3-carbonitrile (3b). This
compound was obtained as colorless prism (methanol), 0.93 g
(22 %), mp 196-197 °C; ir: (potassium bromide): 3270, 3054,
The reactions reported here represents new synthetic
methods towards synthesis of novel quinoline and
chromen derivatives with simple workup and clean
products.
1
2843, 2218, 1629, 1151, 859 cm-1; H nmr: (CDCl3) δ: 1.03 (s,
3H, CH3), 1.14 (s, 3H, CH3), 2.15 (m, 4H, 2CH2), 4.70 (s, 1H,
C4H), 6.22 (bs, 1H, N-H), 7.11 (m, 8H, Ar); Anal. Calcd. for C24
H20 Cl2 N2 O: C, 68.09; H, 4.76; N, 6.62. Found: C, 68.25; H,
4.80; N, 6.81.
EXPERIMENTAL
2-(4-Chlorophenyl)-4-(4-fluorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-oxoquinoline-3-carbonitrile (3c). This
compound was obtained as colorless prism (methanol), 0.85 g
(21 %), mp 205-206 °C; ir: (potassium bromide): 3267, 3054,
Melting points were determined on a Gallenkamp Melting
Point Apparatus, Mod. MFB-595 in open capillary tubes and are
1
uncorrected. The H and 13C nmr spectra were recorded on a
Varian XL-300 spectrometer (300 MHz). Chemical shifts are
reported in ppm from internal tetramethylsilane standard and are
given δ-units. The solvents for nmr spectra was duterio-
chloroform unless otherwise stated. Infrared spectra were taken
on Shimadzu IR-408, a Shimadzu FTIR instrument in
potassium bromide pellets unless otherwise stated. UV
Spectra were recorded on a Shimadzu UV-1601 UV–
visible Spectrophotometer. Compounds for UV scan were
dissolved in methanol. Fluorescence spectra were recorded using
RF-5301 PC Spectrofluorophotometer. Compounds for
fluorescence measurements were dissolved in methanol. UV and
fluorescence scans were recorded from 200 to 500 nm.
Elemental analysis was performed on a Hosli CH-Analyzer and
are within ± 0.4 of the theoretical percentage. All reactions were
monitored by thin layer chromatography, carried out on 0.2 mm
silica gel 60 F-254 (Merk) plates using UV light (254 and 366
nm) for detection. Common reagents-grade chemicals are either
commercially available and were used without further
purification or prepared by standard literature procedures.
2-Aroyl-3-arylacrylonitrile (2a-f). These compounds were
synthesized from p-chloro-, p-bromo- benzoylacetonitrile and
aromatic aldehydes in excellent yields by heating together for 1
hr according to reference [19].
1
2839, 2248, 1628, 1142, 822 cm-1; H nmr: (CDCl3) δ 1.00 (s,
3H, CH3), 1.11 (s, 3H, CH3), 2.12 (m, 4H, 2CH2), 4.73 (s, 1H,
C4H), 6.43 (bs, 1H, N-H), 7.00 (m, 8H, Ar); Anal. Calcd. for C24
H20 ClFN2 O: C, 70.85; H, 4.95; N, 6.88. Found: C, 70.91; H,
4.90; N, 6.96.
2-(4-Bromophenyl)-4-(4-chlorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-oxoquinoline-3-carbonitrile (3d). This
compound was obtained as colorless prism (methanol), 1.16 g
(25 %), mp 191-192 °C; ir: (potassium bromide): 3210, 3014,
1
2813, 2218, 1612, 1142, 854 cm-1; H nmr: (CDCl3) δ 1.02 (s,
3H, CH3), 1.11 (s, 3H, CH3), 2.15 (m, 4H, 2CH2), 4.72 (s, 1H,
C4H), 6.23 (bs, 1H, N-H), 7.09 (m, 8H, Ar); 13C nmr: (CDCl3) δ
22, 27, 31, 41, 44, 51, 92, 116, 117, 119, 125, 125.1, 126, 128,
131, 134, 136, 155, 161, 190. Anal. Calcd. for C24 H20 BrCl N2
O: C, 61.62; H, 4.31; N, 5.99. Found: C, 61.69; H, 4.44; N,
5.90.
2-(4-Bromophenyl)-4-(3-chlorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-oxoquinoline-3-carbonitrile (3e). This
compound was obtained as colorless prism (methanol), 1.12g (24
%), mp 208-209 °C; ir: (potassium bromide): 3081, 2842, 2228,
1629, 1155, 887 cm-1; 1H nmr: (CDCl3) δ 1.00 (s, 3H, CH3), 1.10
(s, 3H, CH3), 2.13 (m, 4H, 2CH2), 4.73 (s, 1H, C4H), 6.19 (bs, 1H,
N-H), 7.15 (m, 8H, Ar); Anal. Calcd. for C24 H20 BrCl N2 O: C,
61.62; H, 4.31; N, 5.99. Found: C, 61.75; H, 4.48; N, 6.08.
2-(4-Bromophenyl)-4-(4-fluorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-oxoquinoline-3-carbonitrile (3f). This
compound was obtained as colorless prism (methanol), 1.17 g
(26 %), mp 219-220 °C; ir: (potassium bromide): 3220, 3034,
General Procedure for the Preparation of 2-(4-haloph-
enyl)-1,4,5,6,7,8-hexahydro-7,7-dimethyl-5-oxo-4-halophenyl-
qinoline-3-carbonitrile (3) and 2-(4-Halophenyl)-1,4,5,-6,7,8-
hexahydro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexyl-
idene)-4-halophenylquinoline-3-carbonitrile (4). A mixture of
the equimolar amount of dimedone (1) (10 mmol), 2-aroyl-3-

670
D. Kendre, R. Toche, M. Jachak
Vol 45
1
2843, 2225, 1645, 1133, 812 cm-1; H nmr: (CDCl3) δ 1.06 (s,
3H, CH3), 1.09 (s, 3H, CH3), 2.12 (m, 4H, 2CH2), 4.69 (s, 1H,
C4H), 6.18 (bs, 1H, N-H), 7.08 (m, 8H, Ar); Anal. Calcd. for C24
H20 BrFN2 O: C, 63.87; H, 4.47; N, 6.21. Found: C, 63.99; H,
4.65; N, 6.09.
C4H), 6.79 (bs, 1H, N-H), 7.19 (m, 8H, Ar); Anal. Calcd. for C32
H30BrFN2 O2: C, 67.02; H, 5.27; N, 4.88. Found: C, 67.16; H,
5.43; N, 4.97.
General Procedure for the Preparation of 2-(4-halophe-
nyl)-5,6,7,8-tetrahydro-7,7-dimethyl-5-oxo-4-halophenyl-4H-
chromene-3-carbonitrile (5) and 2-(4-Halophenyl)-5,6, 7,8-
tetrahydro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclo-
hexylidene)-4-halophenyl-4H-chromene-3-carbonitrile (6). A
mixture of the appropriate amount of dimedone (1) (10 mmol)
and 2-aroyl-3-arylacrylonitrile (2) (10 mmol) in xylene (20 mL)
containing catalytic amount of triethylamine (1 mL) was heated
under reflux for 5 hours. The completion of reaction was
monitored by thin layer chromatography (TLC). The solvent was
removed under reduced pressure, the obtained solid was stirred
in methanol. A colorless solid precipitated out was filtered,
washed with methanol and dried. It contained two compounds,
the mixture obtained was separated by column chromatography
using acetone/toluene as eluent in 1:10 ratio afforded the
compounds (5) and (6) in 25:55 % yield respectively.
2,4-Bis(4-chlorophenyl)-1,4,5,6,7,8-hexahydro-7,7-dimeth-
yl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)quinoline-3-car-
bonitrile (4a). This compound was obtained as colorless prism
(ethanol), 2.18 g (40 %), mp 200-201 °C; ir: (potassium
bromide): 3178, 3064, 2954, 2877, 2214, 1641, 1604, 1145
cm-1; 1H nmr: (CDCl3) δ 1.01 (s, 6H, 2CH3), 1.09 (s, 6H, 2CH3),
2.17 (m, 8H, 4CH2), 5.07 (s, 1H, C4H), 6.78 (bs, 1H, N-H), 7.07
(m, 8H, Ar); 13C nmr: (CDCl3) δ 22, 24, 27, 32, 37, 40, 44, 50,
52, 92, 108, 116, 117, 118, 122, 123, 124, 126, 128, 135, 140,
142, 144, 160, 184. Anal. Calcd. for C32 H30 Cl2 N2 O2: C, 70.46;
H, 5.54; N, 5.14. Found: C, 70.60; H, 5.48; N, 5.08.
4-(3-Chlorophenyl)-2-(4-chlorophenyl)-1,4,5,6,7,8-hexahy-
ro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)
quinoline-3-carbonitrile (4b). This compound was obtained as
colorless prism (ethanol), 2.28 g (42 %), mp 210-211 °C; ir:
(potassium bromide): 3158, 3055, 2944, 2877, 2210, 1648, 1609,
1145, 785 cm-1; H nmr: (CDCl3) δ 1.02 (s, 6H, 2CH3), 1.10 (s,
6H, 2CH3), 2.19 (m, 8H, 4CH2), 5.03 (s, 1H, C4H), 6.75 (bs, 1H,
N-H), 7.09 (m, 8H, Ar); Anal. Calcd. for C32 H30 Cl2 N2 O2: C,
70.46; H, 5.54; N, 5.14. Found: C, 70.55; H, 5.69; N, 5.28.
2-(4-Chlorophenyl)-4-(4-fluorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)
quinoline-3-carbonitrile (4c). This compound was obtained as
colorless prism (ethanol), 2.16 g (41 %), mp 217-218 °C; ir:
(potassium bromide): 3180, 3056, 2954, 2867, 2244, 1648, 1609,
2,4-Bis(4-chlorophenyl)-5,6,7,8-tetrahydro-7,7-dimethyl-5-
oxo-4H-chromene-3-carbonitrile (5a). This compound was
obtained as colorless prism (methanol), 1.06 g (25 %), mp 190-
1
1
191 °C; ir: (potassium bromide): 2215, 1635, 1156, 858cm-1; H
nmr: (CDCl3) δ 1.03 (s, 3H, CH3), 1.17 (s, 3H, CH3), 2.16 (m, 4H,
2CH2), 4.73 (s, 1H, C4H), 7.07 (m, 8H, Ar); 13C nmr: (CDCl3) δ
22, 24, 28, 42, 44, 52, 93, 116, 118, 119, 123, 124, 127, 128, 131,
136, 137, 156, 160, 198. Anal. Calcd. for C24 H19 Cl2 NO2: C,
67.93; H, 4.51; N, 3.30. Found: C, 67.99; H, 4.63; N, 3.47.
4-(3-Chlorophenyl)-2-(4-chlorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-oxo-4H-chromene-3-carbonitrile (5b). This
compound was obtained as colorless prism (methanol), 1.10 g
(26 %), mp 199-200 °C; ir: (potassium bromide): 2225, 1641,
1133, 887 cm-1; H nmr: (CDCl3) δ 1.04 (s, 6H, 2CH3), 1.08 (s,
6H, 2CH3), 2.16 (m, 8H, 4CH2), 5.05 (s, 1H, C4H), 6.75 (bs, 1H,
N-H), 7.17 (m, 8H, Ar); Anal. Calcd. for C32 H30 ClFN2 O2: C,
72.65; H, 5.72; N, 5.30. Found: C, 72.79; H, 5.78; N, 5.48.
1
1
1439, 1365, 1165, 886 cm-1; H nmr: (CDCl3) δ 1.02 (s, 3H,
CH3), 1.18 (s, 3H, CH3), 2.18 (m, 4H, 2CH2), 4.76 (s, 1H, C4H),
7.09 (m, 8H, Ar); Anal. Calcd. for C24 H19Cl2NO2: C, 67.93; H,
4.51; N, 3.30. Found: C, 68.09; H, 4.70; N, 3.41.
2-(4-Bromophenyl)-4-(4-chlorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)
quinoline-3-carbonitrile (4d). This compound was obtained as
colorless prism (ethanol), 2.65 g (45 %), mp 214-215 °C; ir:
(potassium bromide): 3161, 3035, 2967, 2842, 2215, 1639,
2-(4-Chlorophenyl)-4-(4-fluorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-oxo-4H-chromene-3-carbonitrile (5c). This
compound was obtained as colorless prism (methanol), 1.01 g
(25 %), mp 216-217 °C; ir: (potassium bromide): 2235, 1644,
1601, 1143, 785 cm-1; H nmr: (CDCl3) δ 1.03 (s, 6H, 2CH3),
1
1
1409, 1333, 1124, 846 cm-1; H nmr: (CDCl3) δ 1.01 (s, 3H,
1.06 (s, 6H, 2CH3), 2.20 (m, 8H, 4CH2), 5.03 (s, 1H, C4H), 6.72
(bs, 1H, N-H), 7.10 (m, 8H, Ar); 13C nmr: (CDCl3) δ 23, 24, 28,
32, 38, 41, 44, 48, 51, 92, 107, 117, 118, 120, 122, 123, 124,
126, 128, 135, 137, 141, 146, 161, 183. Anal. Calcd. for C32
H30Br Cl N2 O2: C, 65.15; H, 5.13; N, 4.75. Found: C, 65.26; H,
5.28; N, 4.88.
2-(4-Bromophenyl)-4-(3-chlorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)
quinoline-3-carbonitrile (4e). This compound was obtained as
colorless prism (ethanol), 2.70 g (46 %), mp 225-226 °C; ir:
(potassium bromide): 3174, 3062, 2951, 2873, 2224, 1640, 1601,
CH3), 1.12 (s, 3H, CH3), 2.19 (m, 4H, 2CH2), 4.71 (s, 1H, C4H),
7.17 (m, 8H, Ar); Anal. Calcd. for C24 H19ClFNO2: C, 70.67; H,
4.70; N, 3.43. Found: C, 70.84; H, 4.68; N, 3.50.
2-(4-Bromophenyl)-4-(4-chlorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-oxo-4H-chromene-3-carbonitrile (5d). This
compound was obtained as colorless prism (methanol), 1.40 g
(30 %), mp 209-210 °C; ir: (potassium bromide): 2248, 1605,
1
1479, 1344, 1126, 828 cm-1; H nmr: (CDCl3) δ 1.06 (s, 3H,
CH3), 1.14 (s, 3H, CH3), 2.11 (m, 4H, 2CH2), 4.78 (s, 1H, C4H),
7.20 (m, 8H, Ar); 13C nmr: δ 25, 27, 31, 40, 44, 52, 92, 116, 117,
118, 123, 124, 127, 128, 132, 135, 137, 155, 161, 198. Anal.
Calcd. for C24 H19BrClNO2: C, 61.49; H, 4.09; N, 2.99. Found:
C, 61.68; H, 4.13; N, 2.92.
1142, 791 cm-1; H nmr: (CDCl3) δ 1.07 (s, 6H, 2CH3), 1.12 (s,
6H, 2CH3), 2.14 (m, 8H, 4CH2), 5.04 (s, 1H, C4H), 6.71 (bs, 1H,
N-H), 7.06 (m, 8H, Ar); Anal. Calcd. for C32 H30Br Cl N2 O2: C,
65.15; H, 5.13; N, 4.75. Found: C, 65.32; H, 5.18; N, 4.90.
1
2-(4-Bromophenyl)-4-(3-chlorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-oxo-4H-chromene-3-carbonitrile (5e). This
compound was obtained as colorless prism (methanol), 1.31 g
(28 %), mp 222-223 °C; ir: (potassium bromide): 2240, 1620,
2-(4-Bromophenyl)-4-(4-fluorophenyl)-1,4,5,6,7,8-hexahy-
dro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)
quinoline-3-carbonitrile (4f). This compound was obtained as
colorless prism (ethanol), 2.75 g (48 %), mp 232-233 °C
(ethanol); ir: (potassium bromide): 3187, 3046, 2945, 2877,
1
1419, 1324, 1116, 868 cm-1; H nmr: (CDCl3) δ 1.05 (s, 3H,
CH3), 1.15 (s, 3H, CH3), 2.15 (m, 4H, 2CH2), 4.75 (s, 1H, C4H),
7.05 (m, 8H, Ar); Anal. Calcd. for C24H19BrClNO2: C, 61.49; H,
4.09; N, 2.99. Found: C, 61.65; H, 4.24; N, 3.12.
1
2233, 1635, 1600, 1145, 775 cm-1; H nmr: (CDCl3) δ 1.03 (s,
6H, 2CH3), 1.07 (s, 6H, 2CH3), 2.20 (m, 8H, 4CH2), 5.13 (s, 1H,

May-Jun 2008
Michael Addition of Dimedone with α,β-unsaturated Ketones
671
2-(4-Bromophenyl)-4-(4-fluorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-oxo-4H-chromene-3-carbonitrile (5f). This
compound was obtained as colorless prism (methanol), 1.44 g
(32 %), mp 234-235 °C; ir: (potassium bromide): 2235, 1645,
(potassium bromide): 2233, 1621, 1608, 1467, 1133, 879, 745
cm-1; 1H nmr: (CDCl3) δ 1.00 (s, 6H, 2CH3), 1.10 (s, 6H, 2CH3),
2.16 (m, 8H, 4CH2), 5.08 (s, 1H, C4H), 7.17 (m, 8H, Ar); Anal.
Calcd. for C32 H29BrClNO3: C, 65.04; H, 4.95; N, 2.37. Found:
C, 65.20; H, 5.10; N, 2.50.
1
1415, 1375, 1155, 889 cm-1; H nmr: (CDCl3) δ 1.00 (s, 3H,
CH3), 1.13 (s, 3H, CH3), 2.13 (m, 4H, 2CH2), 4.70 (s, 1H, C4H),
7.17 (m, 8H, Ar); Anal. Calcd. for C24H19BrFNO2: C, 63.73; H,
4.23; N, 3.10. Found: C, 63.78; H, 4.42; N, 3.22.
2-(4-Bromophenyl)-4-(4-fluorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)-4H-
chromene-3-carbonitrile (6f). This compound was obtained as
colorless prism (ethanol), 3.15 g (55 %), mp 248-249 °C; ir:
(potassium bromide): 2211, 1641, 1601, 1481, 1141, 881, 761
cm-1; 1H nmr: (CDCl3) δ 1.03 (s, 6H, 2CH3), 1.13 (s, 6H, 2CH3),
2.17 (m, 8H, 4CH2), 5.08 (s, 1H, C4H), 7.20 (m, 8H, Ar); Anal.
Calcd. for C32H29BrFNO3: C, 66.90; H, 5.09; N, 2.44. Found: C,
66.99; H, 5.20; N, 2.55.
Acknowledgement. Authors thank University Grants
Commission (UGC), New Delhi, India for financial support and
Prof. D. D. Dhavale, Department of Chemistry, University of
Pune for his encouragement and useful discussion.
2,4-Bis(4-chlorophenyl)-5,6,7,8-tetrahydro-7,7-dimethyl-5-
(4,4-dimethyl-2,6-dioxocyclohexylidene)-4H-chromene-3-
carbonitrile (6a). This compound was obtained as colorless
prism (ethanol), 2.45 g (45 %), mp 220-221 °C; ir: (potassium
bromide): 2210, 1641, 1604, 1487, 1145, 889, 765 cm-1; 1H nmr:
(CDCl3) δ 1.03 (s, 6H, 2CH3), 1.06 (s, 6H, 2CH3), 2.11 (m, 8H,
4CH2), 5.07 (s, 1H, C4H), 7.08 (m, 8H, Ar); 13C nmr: (CDCl3) δ
22, 24, 27, 30, 32, 37, 40, 44, 52, 92, 108, 116, 118, 119, 122,
124, 125, 126, 128, 135, 138, 140, 145, 160, 184. Anal. Calcd.
for C32H29Cl2NO3: C, 70.33; H, 5.35; N, 2.56. Found: C, 70.45;
H, 5.46; N, 2.66.
4-(3-Chlorophenyl)-2-(4-chlorophenyl)-5,6,7,8-tetra-
hydro-7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexyl-
idene)-4H-chromene-3-carbonitrile (6b). This compound was
obtained as colorless prism (ethanol), 2.56 g (47 %), mp 229-
230 °C; ir: (potassium bromide): 2210, 1643, 1603, 1483, 1143,
REFERENCES AND NOTES
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[2] Uray, G.; Niederreiter, K. S. Belaj, F.; Fabin, W. Helvetica
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Acta. 2004, 87, 1.
1
883, 763 cm-1; H nmr: (CDCl3) δ 0.99 (s, 6H, 2CH3), 1.05 (s,
6H, 2CH3), 2.14 (m, 8H, 4CH2), 5.09 (s, 1H, C4H), 7.15 (m, 8H,
Ar); Anal. Calcd. for C32H29Cl2NO3: C, 70.33; H, 5.35; N, 2.56.
Found: C, 70.42; H, 5.42; N, 2.74.
[4] Basta, A.; Girgis, A.; Houssni, S. Dyes Pigm. 2002, 54, 1.
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[10] Gorobets, N.; Yousefi, B. H.; Belaj, F.; Kappe, C.
Tetrahedron. 2004, 60, 8633.
2-(4-Chlorophenyl)-4-(4-fluorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)-4H-
chromene-3-carbonitrile (6c). This compound was obtained as
colorless prism (ethanol), 2.54 g (48 %), mp 239-240 °C; ir:
(potassium bromide), 2215, 1645, 1605, 1485, 1145, 885, 765
cm-1; 1H nmr: (CDCl3) δ 0.98 (s, 6H, 2CH3), 1.08 (s, 6H, 2CH3),
2.13 (m, 8H, 4CH2), 5.05 (s, 1H, C4H), 7.04 (m, 8H, Ar); Anal.
Calcd. for C32H29ClFNO3: C, 72.51; H, 5.51; N, 2.64. Found: C,
72.65; H, 5.46; N, 2.76.
2-(4-Bromophenyl)-4-(4-chlorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)-4H-
chromene-3-carbonitrile (6d). This compound was obtained as
colorless prism (ethanol), 2.95 g (50 %), mp 231-232 °C; ir:
(potassium bromide): 2235, 1638, 1610, 1477, 1159, 891, 755
cm-1; 1H nmr: (CDCl3) δ 1.09 (s, 6H, 2CH3), 1.14 (s, 6H,2 CH3),
2.12 (m, 8H, 4CH2), 5.11 (s, 1H, C4H), 7.14 (m, 8H, Ar); 13C
nmr: (CDCl3) δ 18, 24, 25, 32, 36, 42, 44, 51, 92, 107, 118,
118.2, 119, 124, 124, 126, 126.1, 128, 135, 136, 141, 145, 159,
187. Anal. Calcd. for C32H29BrClNO3: C, 65.04; H, 4.95; N,
2.37. Found: C, 65.15; H, 4.90; N, 2.54.
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2-(4-Bromophenyl)-4-(3-chlorophenyl)-5,6,7,8-tetrahydro-
7,7-dimethyl-5-(4,4-dimethyl-2,6-dioxocyclohexylidene)-4H-
chromene-3-carbonitrile (6e). This compound was obtained as
colorless prism (ethanol), 3.06 g (52 %), mp 241-242 °C; ir:
[18] Jachak, M. N.; Kendre, D. B.; Avhale, A. B.; Toche, R. B.;
Medhane, V. J. Org. Prep. Proced. Int. 2006, 38(3), 313.
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1977, 18, 1835.