A Novel, Multi-component Method of Preparation of Quinolines Using Recyclable CeO2-TiO2 Nanocomposite Catalyst under Solvent-free Conditions

Full text of DOI:10.1080/00304948.2019.1577121

Organic Preparations and Procedures International
The New Journal for Organic Synthesis
ISSN: 0030-4948 (Print) 1945-5453 (Online) Journal homepage: https://www.tandfonline.com/loi/uopp20
A Novel, Multi-component Method of Preparation
of Quinolines Using Recyclable CeO2-TiO2
Nanocomposite Catalyst under Solvent-free
Conditions
Sibaditya Khan, Mallikarjun Agasar, Arnab Ghosh & Rangappa S. Keri
To cite this article: Sibaditya Khan, Mallikarjun Agasar, Arnab Ghosh & Rangappa S. Keri (2019):
A Novel, Multi-component Method of Preparation of Quinolines Using Recyclable CeO2-TiO2
Nanocomposite Catalyst under Solvent-free Conditions, Organic Preparations and Procedures
International, DOI: 10.1080/00304948.2019.1577121
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Organic Preparations and Procedures International, 0:1–8,
# 2019 Taylor & Francis Group, LLC
ISSN: 0030-4948 print / 1945-5453 online
DOI: 10.1080/00304948.2019.1577121
A Novel, Multi-component Method of Preparation
of Quinolines Using Recyclable CeO2-TiO2
Nanocomposite Catalyst under Solvent-
free Conditions
Sibaditya Khan, Mallikarjun Agasar, Arnab Ghosh, and
Rangappa S. Keri
Centre for Nano and Material Sciences, Jain University, Jain Global Campus,
Kanakapura, Ramanagaram, Bangalore 562112, India
In view of our ongoing interest in nanocatalysis, multicomponent reactions (MCR) and
solvent free synthesis, we have developed a new procedure for the preparation of quinolines.
The procedure involves substituted aromatic anilines, aldehydes and acetophenone and is
catalyzed by CeO2-TiO2 under solvent-free conditions (Scheme 1). We now present a study
on the substrate scope and the effect of temperature, solvent, and catalyst concentration for
this environmentally friendly protocol.
Aniline (1), benzaldehyde (2) and acetophenone (3) were selected as model substrates
to optimize the reaction conditions. The reaction was carried out in several solvents includ-
ing DMF, toluene, ethanol, 1,4-dioxane and solvent free as summarized in Table 1.
Reaction in solvents took longer, and gave lower yields, when compared to the solvent-free
reaction. We view this as a fortunate combination of efficiency and green characteristics.
In order to investigate the effect of temperature on the reaction, the concentration
of catalyst was kept constant at 2 wt.% and a mixture of the substrates was heated at
temperatures ranging from 30–80ꢀC. The reaction was monitored by TLC under solvent
free conditions. After stirring for 360 min, no reaction occurred at room temperature.
Increasing the reaction temperature to 70ꢀC (Table 2, entry 5) resulted in a better yield
and shorter reaction time. Further increases in the temperature did not show any mater-
ial improvement in the yield or reaction time. Therefore, 70ꢀC was chosen as the reac-
tion temperature for all further reactions.
We studied the effect of catalyst concentration on the reaction by varying the
amounts of catalyst (0.5, 1, 2, and 5 wt. %) at 70ꢀC under solvent-free conditions.
According to the results presented in Table 3, in the absence of the CeO2-TiO2, the
reaction did not produce any products after refluxing for 70ꢀC for 360 min (Table 3,
entry 1). The best results were obtained using 1 wt. % of CeO2-TiO2 (Table 3, entry 3)
Received February 21, 2018; in final form October 21, 2018.
Address correspondence to Rangappa S. Keri, Centre for Nano and Material Sciences, Jain
University, Jain Global Campus, Kanakapura, Ramanagaram, Bangalore 562112, India. E-mail:
keriphd@gmail.com
Color versions of one or more of the figures in the article can be found online at www.tandfon-
line.com/uopp.
1

2
Keri et al.
Scheme 1. One-pot synthesis of 2,4-disubstituted quinolines using CeO2-TiO2 under solvent-
free conditions.
Table 1
CeO2-TiO2 Catalyzed One-pot Synthesis of 4-Diphenylquinolinea (4a) with and with-
out Solvent
Entry
Solvent
DMF
Toluene
Ethanol
Dioxane
Time (min)b
Yield (%)c
1
2
3
4
5
150
150
120
180
90
75
68
78
81
95
Solvent free
aReaction conditions: Aniline (1 mmol), benzaldehyde (1 mmol), and acetophenone (1 mmol),
solvent (5 mL) or no solvents 80ꢀC using 2 wt. % of CeO2-TiO2 catalyst.
bReaction time is monitored by TLC.
cIsolated yields.
Table 2
Temperature Optimization for the Synthesis 2,4-Diphenylquinolinea (4a) under Solvent
free Conditions using CeO2-TiO2 Catalyst
Entry
Temperature (ꢀC)
Time (min)b
Yield (%)c
–––
1
2
3
4
5
6
7
r.t
40
50
60
70
80
90
360
240
240
160
90
65
68
76
95
95
94
90
90
aReaction conditions: Aniline (1 mmol), benzaldehyde (1 mmol), and acetophenone (1 mmol),
at various temperatures under solvent-free conditions using 2 wt.% of CeO2-TiO2 catalyst.
bReaction time monitored by TLC.
cIsolated yields.
and the data suggest that the catalyst shows excellent activity at lower concentration, in
terms of duration and yield. Use of higher amounts of catalyst improved neither the
yield nor the reaction time.
Summarizing, the best result was obtained when the CeO2-TiO2 catalyst was at
1 wt. %, while the reaction was performed at 70ꢀC under solvent-free conditions. Under

Preparation of Quinolines
3
Table 3
Effect of Catalyst Concentration on the Synthesis of 2,4-Diphenylquinolinea (4a)
Entry
Catalyst concentration (wt. %)
Time (min)b
Yield (%)c
1
2
3
4
5
—
0.5
1
2
5
360
180
90
90
90
—
77
94
93
90
aReaction conditions: Aniline (1 mmol), benzaldehyde (1 mmol), and acetophenone (1 mmol),
at 70ꢀC under solvent-free conditions at various catalyst concentrations.
bReaction time monitored by TLC.
cIsolated yields.
the optimized conditions, the model reaction gave a 95% yield of 2,4-diphenylquinoline
(4a) after 90 min. With the optimized reaction conditions in hand, we performed the
reaction with different substituted anilines and aldehydes (Scheme 2).
We have compared our method using CeO2-TiO2 with reported catalysts such as
TiO2, Yb(Pfb)3 and silver catalyst using 4a as a representative example (Table 4). The
results clearly reveal that the present protocol could serve as a better method than some
previously reported (Table 4).
The reusability and recyclability of the CeO2-TiO2 catalyst was examined in the
reaction of aniline, benzaldehyde, and acetophenone under solvent-free conditions.
After completion, ethyl alcohol was added to the reaction mixture, which was stirred
and then boiled for a few minutes to dissolve the product. The insoluble catalyst was
filtered, and the filtrate was evaporated in vacuo to dryness to get the product. The
recovered catalyst was reused for successive experiments. At the end of five cycles, the
yield had only diminished a few percent to 89%
In summary, we have successfully developed a facile, efficient, environmentally
benign, multicomponent synthesis of 2,4-disubstituted quinolines using 1 wt.% CeO2-
TiO2 catalyst, prepared by the wet-impregnation method, under solvent-free conditions.
Reactions of substituted anilines, and aldehydes with acetophenone resulted in good
yields of the corresponding products, and the reaction conditions were optimized.
Considering the commercial availability of the starting materials and the ease of prepar-
ation of the catalyst, as well as the low cost, we hope that this method will find numer-
ous applications. Further investigations on the scope of the reaction and its applications
in organic synthesis and drug discovery are ongoing in our laboratory.
Experimental Section
Catalyst Preparation
Materials
Titanium(IV) chloride (Lobachemie), and cerous nitrate hexahydrate (SD Fine Chem.
Ltd.) were purchased and used without further purification. Analytical grade reagents
were purchased from Sigma-Aldrich, Fluka and Acros. Solvents and were dried accord-
ing to standard methods.1

4
Keri et al.
Scheme 2. Examples of 2,4-disubstituted quinoline derivatives. Reaction conditions: Aniline
(1 mmol), benzaldehyde (1 mmol), and acetophenone (1 mmol), at 70ꢀC under solvent-free condi-
tions at 1 wt.% of CeO2-TiO2 catalyst. Yields of isolated products are reported.
Synthesis of Single Oxides by Precipitation Method
TiO2 and CeO2 single oxides were synthesized by a simple precipitation method by tak-
ing ammonium hydroxide as precipitating agent. In a typical experiment, the required
quantities of TiCl4 or Ce(NO3)3ꢁ6H2O were dissolved in deionized water to which
dilute aqueous ammonia (1M) was added dropwise with vigorous stirring until the

Preparation of Quinolines
5
Table 4
Comparison of Efficiency of Catalysts for Synthesis of 4-Diphenylquinolinea (4a)
Entry
Catalysts
Reaction time (min)
Yield (%)b
1
2
3
4
5
TiO2
CeO2
Yb(Pfb)3
AgoTf, HoTf
CeO2-TiO2
300
900
120
600
90
53
32
86
85
95
aReaction conditions: Aniline (1 mmol), benzaldehyde (1 mmol), and acetophenone (1 mmol),
at 70ꢀC under solvent-free conditions (similar protocols for all reactions).
bIsolated yields.
precipitation was complete (pH ¼ 9.5). The resultant precipitates were aged at room
temperature under stirring for 12h, filtered and washed with deionized water until free
from impurities. The obtained cake was oven dried at 120ꢀC foꢂr 112h and finally cal-
cined at 500ꢀC for 4h in static air with a ramping rate of 3ꢀC min
.
Synthesis of Mixed Oxides by Impregnation Method
For the synthesis of 5 wt.% CeO2-TiO2, the required amount of Ce(NO3)2ꢁH2O was dis-
solved in deionized water and wet impregnated on TiO2 under constant stirring. The
resultant powder was dried at 100ꢀC for 12h and then finally calcined in static air at
600ꢀC for 4h with a ramping rate of 3ꢀC minꢂ1. The catalyst was fully characterized,
and all data supported the catalyst as herein reported. Complete data including adsorp-
tion and desorption isotherms of nitrogen, dextral properties, X-ray diffraction patterns,
scanning electron micrographs and element mapping, were submitted for review by the
editors and are available from the corresponding author upon request.
Quinoline Characterization Techniques
1
The H and 13C NMR spectra were recorded on Bruker AVANCE III spectrometers at
300 and 75 MHz, respectively. Chemical shifts (d) are reported in ppm from the stand-
ard internal reference tetramethylsilane (TMS). Mass spectra were recorded on
Micromass Quattro II instrument using the electrospray ionization (ESI) technique,
showing the (M þ H) peak as a prominent base peak. The homogeneity of the com-
pounds was determined by TLC (silica gel 60 F254 (Merck) detected by UV light
(254 nm) and iodine vapors; (DCM: MeOH (10:1)). The melting points of the products
were determined by open capillaries and are uncorrected.
General Procedure for the Synthesis of 2,4–Disubstituted Quinoline Derivatives (4a-m)
A mixture of aniline (1mmol), benzaldehyde (1mmol), and acetophenone (1mmol) and
CeO2-TiO2 (1 wt. %) was refluxed within an oil bath at 70ꢀC under stirring for the
appropriate time shown in Scheme 2. After completion of the reaction as monitored by
TLC, ethanol (10 mL) was added, and the catalyst was recovered by filtration. The mix-
ture was evaporated under reduced pressure and yielded high purity products. All the
1
synthesized products are known compounds and were characterized using ATR-IR, H
NMR, 13C NMR and mass spectral techniques. Each compound had a satisfactory

6
Keri et al.
elemental analysis. The mp and spectral data of the reported compounds matched
reported data. Similar protocols were followed in our laboratory for the comparison
studies shown in Table 4.
Characterization Data for the Synthesized Quinolines
2,4-Diphenylquinoline (4a). Aniline (1a), benzaldehyde (2a) and acetophenone (3)
afforded the pure title product; mp. 121-123ꢀC, lit mp 120ꢀC2; IR tmax (KBr, cmꢂ1):
1621 (-C ¼ N stretching), 1575 (-C ¼ C stretching); 1H NMR (300MHz, CDCl3, d ppm):
8.31 (d, J¼8.3Hz, 1H), 8.20 (d, J¼7.1Hz, 2H), 7.88 (d, J¼8.3Hz, 1H), 7.82 (s, 1H), 7.73
(t, J¼7.2Hz, 1H), 7.62–7.41 (m, 9H); 13C NMR (75 MHz, CDCl3, d ppm): 156.8, 150.4,
146.5, 139.5, 138.8, 132.0, 129.9, 129.7, 129.4, 129.2, 129.0, 128.4, 128.0, 127.8, 127.6,
127.5, 127.3, 127.0, 124.3, 116.8, 101.2; MS-ESI (m/z): 281 (Mþ), 282 (M þ 1)þ.
Anal. Calcd. for C21H15N: C, 89.65; H, 5.37; N, 4.98. Found: C, 89.77; H, 5.42;
N, 4.78.
4-Phenyl-2-(p-tolyl)quinoline (4b). Aniline (1a), p-methyl-benzaldehyde (2b) and ace-
tophenone (3) afforded the pure title product; mp. 104–106ꢀC, lit mp 105ꢀC2; IR tmax
1
(KBr, cmꢂ1): 1616 (-C ¼ N stretching), 1566 (-C ¼ C stretching); H NMR (300MHz,
CDCl3, d ppm): 8.20-8.11 (m, 3H), 7.79 (s, 1H), 7.65 (s, 1H), 7.41–7.29 (m, 9H), 2.39
(s, 3H); 13C NMR (75 MHz, CDCl3, d ppm): 157.0, 150.7, 146.0, 139.2, 137.0, 131.5,
130.2, 129.9, 129.7(2C), 129.4 (3C), 127.8, 127.5, 127.2, 125.2, 123.3, 123.0, 117.1,
102.1, 21.7; MS-ESI (m/z): 295 (Mþ), 296 (M þ 1)þ.
Anal. Calcd. for C22H17N: C, 89.46; H, 5.80; N, 4.74. Found: C, 89.61; H, 5.66; N, 4.79.
2-(4-Methoxyphenyl)-4-phenylquinoline (4c). Aniline (1a), p-methoxy-benzaldehyde
(2c) and acetophenone (3) afforded the pure title product; mp. 132–134ꢀC, lit mp
1
134ꢀC2; IR tmax (KBr, cmꢂ1): 1623 (-C ¼ N stretching), 1571 (-C ¼ C stretching); H
NMR (300MHz, CDCl3, d ppm): 8.19-8.10 (m, 3H), 7.80 (s, 1H), 7.58–7.40 (m, 9H),
7.18 (d, J¼2.2Hz, 1H), 2.85 (s, 3H); 13C NMR (75 MHz, CDCl3, d ppm): 159.8, 156.4,
150.5, 146.2, 139.3, 132.2, 131.5, 130.2, 129.4 (3C), 128.2 (2C), 127.7, 127.3, 127.0,
124.9, 118.5, 115.1, 114.5, 102.5, 56.1; MS-ESI (m/z): 311 (Mþ), 312 (M þ 1)þ.
Anal. Calcd. for C22H17NO: C, 84.86; H, 5.50; N, 4.50. Found: C, 85.03; H, 5.41;
N, 4.62.
2-(4-Chlorophenyl)-4-phenylquinoline (4d). Aniline (1a), p-chloro-benzaldehyde (2d)
and acetophenone (3) afforded the pure title product; mp. 104–106ꢀC, lit mp 105ꢀC2; IR
tmax (KBr, cmꢂ1): 1616 (-C ¼ N stretching), 1560 (-C ¼ C stretching); 1H NMR
(300MHz, CDCl3, d ppm): 8.21-8.11 (m, 3H), 7.95 (d, J¼2.2Hz, 1H), 7.82 (s, 1H), 7.64
(dd, J¼9.1,2.2Hz, 1H), 7.61–7.43 (m, 8H); 13C NMR (75 MHz, CDCl3, d ppm): 156.1,
150.1, 145.5, 139.0, 137.5, 132.5, 131.2, 129.5, 129.2 (3C), 129.0 (2C), 128.5, 128.2,
127.7, 127.3, 127.0, 124.2, 116.7, 102.8; MS-ESI (m/z): 316 (Mþ), 317 (M þ 1)þ.
Anal. Calcd. for C21H14ClN: C, 79.87; H, 4.47; N, 4.44. Found: C, 79.65; H, 4.62;
N, 4.52.
2-(2-Nitrophenyl)-4-phenylquinoline (4e). Aniline (1a), o-nitro-benzaldehyde (2e) and
acetophenone (3) afforded the pure title product; mp. 140–143ꢀC; IR tmax (KBr, cmꢂ1):
1
1632 (-C ¼ N stretching), 1539 (-C ¼ C stretching), 1462 (-NO2 stretching); H NMR
(300MHz, CDCl3, d ppm): 8.25 (d, J¼7.8Hz, 1H), 8.09–7.95 (m, 4H), 7.90-7.73 (m,
4H), 7.64–7.41 (m, 5H); 13C NMR (75 MHz, CDCl3, d ppm): 156.5, 150.4, 147.5,

Preparation of Quinolines
7
145.6, 139.4, 134.9, 132.9, 131.7, 129.9, 129.4 (3C), 129.2 (2C), 128.4, 128.0, 127.4,
127.1, 125.6, 124.7, 117.7, 102.1; MS-ESI (m/z): 326 (Mþ), 327 (M þ 1)þ.
Anal. Calcd. for C21H14N2O2: C, 77.29; H, 4.32; N, 8.58. Found: C, 77.35; H,
4.52; N, 8.29.
2-(3-Nitrophenyl)-4-phenylquinoline (4f). Aniline (1a), m-nitro-benzaldehyde (2f) and
acetophenone (3) afforded the pure title product; mp. 134–136ꢀC; IR tmax (KBr, cmꢂ1):
1
1636 (-C ¼ N stretching), 1542 (-C ¼ C stretching), 1460 (-NO2 stretching); H NMR
(300MHz, CDCl3, d ppm): 8.94 (s, 1H), 8.62 (dd, J¼7.8, 1.5Hz, 1H), 8.62 (d,
J¼7.5 Hz, 1H), 8.23 (d, J¼7.5 Hz, 1H), 8.09-7.92 (m, 2H), 7.80–7.75 (m, 4H),
7.61–7.41 (m, 5H); 13C NMR (75 MHz, CDCl3, d ppm): 156.1, 150.2, 148.1, 145.3,
139.1, 134.2, 133.1, 132.0, 130.1, 129.7 (3C), 129.1 (2C), 127.8, 123.3, 122.9, 117.7,
104.1, 102.1; MS-ESI (m/z): 326 (Mþ), 327 (M þ 1)þ.
Anal. Calcd. for C21H14N2O2: C, 77.29; H, 4.32; N, 8.58. Found: C, 77.20; H,
4.48; N, 8.32.
2-(4-Nitrophenyl)-4-phenylquinoline (4g). Aniline (1a), p-nitro-benzaldehyde (2g) and
acetophenone (3) afforded the pure title product; mp. 147–148ꢀC; IR tmax (KBr, cmꢂ1):
1
1651 (-C ¼ N stretching), 1562 (-C ¼ C stretching), 1472 (-NO2 stretching); H NMR
(300MHz, CDCl3, d ppm): 8.45–8.32 (m, 4H), 8.28 (d, J¼8.4Hz, 1H), 8.00 (d,
J¼7.5Hz, 2H), 7.79 (s, 1H), 7.71-7.59 (m, 2H), 7.55–7.41 (m, 4H); 13C NMR (75 MHz,
CDCl3, d ppm): 156.7, 150.8, 148.8, 145.1, 139.7, 134.2, 133.4, 131.7, 129.9, 129.3
(3C), 129.0 (2C), 127.4, 124.4, 123.1, 122.7, 117.2, 102.7; MS-ESI (m/z): 326 (Mþ),
327 (M þ 1)þ.
Anal. Calcd. for C21H14N2O2: C, 77.29; H, 4.32; N, 8.58. Found: C, 77.41; H,
4.43; N, 8.53.
6-Methyl-2,4-diphenylquinoline (4h). p-Methyl-aniline (1b), benzaldehyde (2a) and
acetophenone (3) afforded the pure title product; mp. 123–124ꢀC, lit mp 126ꢀC2; IR tmax
1
(KBr, cmꢂ1): 1629 (-C ¼ N stretching), 1572 (-C ¼ C stretching); H NMR (300MHz,
CDCl3, d ppm): 8.19–8.10 (m, 3H), 7.72 (s, 1H), 7.62 (s, 1H), 7.59-7.49 (m, 4H),
7.44–7.30 (m, 5H), 2.36 (s, 3H); 13C NMR (75 MHz, CDCl3, d ppm): 155.2, 150.1,
144.1, 139.4, 138.9, 132.3, 131.4, 129.7, 129.4, 129.2, 129.0, 128.7, 128.4, 127.6, 127.5,
127.3, 127.0, 126.4, 124.3, 117.4, 102.0, 22.5; MS-ESI (m/z): 295 (Mþ), 296 (M þ 1)þ.
Anal. Calcd. for C22H17N: C, 89.46; H, 5.80; N, 4.74; Found: C, 89.71; H, 5.62;
N, 4.89.
6-Methoxy-2,4-diphenylquinoline (4i). p-Methoxy-aniline (1c), benzaldehyde (2a) and
acetophenone (3) afforded the pure title product; mp. 116-117ꢀC, lit mp 118ꢀC2; IR
tmax (KBr, cmꢂ1): 1635 (-C ¼ N stretching), 1566 (-C ¼ C stretching); 1H NMR
(300MHz, CDCl3, d ppm): 8.17-8.12 (m, 3H), 7.74 (s, 1H), 7.62–7.54 (m, 4H),
7.47–7.35 (m, 5H), 7.18 (d, J¼2.4Hz, 1H), 3.87 (s, 3H); 13C NMR (75 MHz, CDCl3, d
ppm): 155.7, 152.2, 146.5, 139.7, 138.1, 132.7, 131.3, 130.7, 130.2, 129.7, 129.2,
128.9, 128.3, 128.0, 127.8, 127.4, 126.8, 125.1, 123.2, 115.1, 101.8, 55.4; MS-ESI (m/
z): 311 (Mþ), 312 (M þ 1)þ.
Anal. Calcd. for C22H17NO: C, 84.86; H, 5.50; N, 4.50. Found: C, 84.75; H, 5.41;
N, 4.64.
6-Fluoro-2,4-diphenylquinoline (4j). p-Fluoro-aniline (1c), benzaldehyde (2a) and ace-
tophenone (3) afforded the pure title product; mp. 128–130ꢀC; IR tmax (KBr, cmꢂ1):
1630 (-C ¼ N stretching), 1552 (-C ¼ C stretching); 1H NMR (300MHz, CDCl3, d

8
Keri et al.
ppm): 8.20 (dd, J¼8.7, 5.3Hz, 1H), 8.15-8.11 (m, 2H), 7.81 (s, 1H), 7.74–7.63 (m, 5H),
7.61–7.43 (m, 5H); 13C NMR (75 MHz, CDCl3, d ppm): 157.5, 155.2, 149.2, 142.7,
139.1, 130.3, 130.0, 129.7, 129.0, 128.7, 128.3, 128.0, 127.5, 127.2, 126.7, 125.4,
125.0, 122.1, 121.2, 108.7, 103.1; MS-ESI (m/z): 299 (Mþ), 300 (M þ 1)þ.
Anal. Calcd. for C22H14FN: C, 84.26; H, 4.71; N, 4.68. Found: C, 84.02; H, 4.92; N, 4.58.
8-Chloro-2,4-diphenylquinoline (4k). o-Chloro-aniline (1d), benzaldehyde (2a) and
acetophenone (3) afforded the pure title product; mp. 112–114ꢀC, lit mp 114ꢀC2; IR
tmax (KBr, cmꢂ1): 1638 (-C ¼ N stretching), 1545 (-C ¼ C stretching); 1H NMR
(300MHz, CDCl3, d ppm): 8.29 (d, J¼2.2Hz, 1H), 8.17–8.10 (m, 2H), 7.80 (d,
J¼8.6Hz, 1H), 7.76 (s, 1H), 7.60-7.51 (m, 4H), 7.48–7.43 (m, 4H), 7.36 (dd,
J¼2.2,9.0Hz, 1H); 13C NMR (75 MHz, CDCl3, d ppm): 157.0, 150.2, 140.8, 139.2,
138.2, 133.7, 130.5, 129.8, 129.5, 129.2, 128.5, 128.1, 127.9, 127.4, 127.0, 126.5,
125.6, 124.1, 122.1, 121.7, 103.1; MS-ESI (m/z): 316 (Mþ), 317 (M þ 1)þ.
Anal. Calcd. for C21H14ClN: C, 79.87; H, 4.47; N, 4.44. Found: C, 79.65; H, 4.55;
N, 4.62.
7-Chloro-2,4-diphenylquinoline (4l). m-Chloro-aniline (1e), benzaldehyde (2a) and
acetophenone (3) afforded the pure title product; mp. 118–120ꢀC, lit mp 118ꢀC2; IR
tmax (KBr, cmꢂ1): 1622 (-C ¼ N stretching), 1530 (-C ¼ C stretching); 1H NMR
(300MHz, CDCl3, d ppm): 8.40–8.32 (m, 2H), 7.94 (s, 1H), 7.83 (dd, J¼7.6,1.2Hz,
1H), 7.76 (dd, J¼7.6, 1.2Hz, 1H), 7.66–7.54 (m, 4H), 7.50–7.36 (m, 4H), 7.36 (dd,
J¼8.4,7.0Hz, 1H); 13C NMR (75 MHz, CDCl3, d ppm): 156.6, 149.1, 145.8, 139.7,
139.0, 134.5, 130.2, 130.0, 129.6, 129.3, 128.4, 128.0, 127.7, 127.2, 126.9, 126.0,
125.1, 123.4, 120.2, 115.5, 102.7; MS-ESI (m/z): 316 (Mþ), 317 (M þ 1)þ.
Anal. Calcd. for C21H14ClN: C, 79.87; H, 4.47; N, 4.44 . Found: C, 79.93; H, 4.62;
N, 4.30.
6-Chloro-2,4-diphenylquinoline (4m). p-Chloro-aniline (1e), benzaldehyde (2a) and
acetophenone (3) afforded the pure title product; mp. 121–123ꢀC, lit mp 125ꢀC2; IR
tmax (KBr, cmꢂ1): 1625 (-C ¼ N stretching), 1526 (-C ¼ C stretching); 1H NMR
(300MHz, CDCl3, d ppm): 8.42–8.32 (m, 3H), 7.84 (d, J¼2.4Hz, 1H), 7.84 (s, 1H),
7.74 (dd, J¼9.2, 2.2Hz, 1H), 7.69-7.57 (m, 4H), 7.52–7.39 (m, 4H); 13C NMR
(75 MHz, CDCl3, d ppm): 156.0, 150.1, 143.2, 139.3, 138.2, 132.1, 131.5, 130.0, 129.8,
129.5, 129.1, 128.7, 127.8, 127.0, 126.4, 125.5, 125.0, 123.4, 120.5, 114.4, 103.1; MS-
ESI (m/z): 316 (Mþ), 317 (M þ 1)þ.
Anal. Calcd. for C21H14ClN: C, 79.87; H, 4.47; N, 4.44. Found: C, 79.77; H, 4.77;
N, 4.56.
Acknowledgments
The authors thank Jain University, Bangalore, Karnataka, India, for financial support.
References
1. W. L. F. Armarego, and D. D. Perrin, “Purification of Laboratory Chemicals,” p. 10,
Butterworth-Heinemann, Oxford, 1999.
2. C. Yao, B. Qin, H. Zhang, J. Lu, D. Wang, and S. Tu, RSC Adv., 2, 3759 (2012).